How to format my Mac and reinstall OS X Yosemite?

Hello, is there steps I can follow somewhere to format and reinstall yosemity properly? I tried to boot into the recovery partition and I agreed to the terms and choose the option to reinstall, but then it got quiet and nothing happened. Just want to make sure I do it rite. Or should I download the file from the app store? And can it boot from the super dvd drive?


#1 Hi

Hi! Older to reinstall osX do the steps this.
Restart your mac, and wen you hear the sound startup system press and hold commend and r keys for a haf me nit and after this tern on voiceovefr.
In os10 utilities chuse "disk utilities" interact with this and chuse this.
Dpress commend up erro and chuse macintosh hd and bchuse delete disk. Back to osX utilities and chuse install os10.

#2 RE: How to format my Mac and reinstall OS X Yosemite?

As the story begins, I did this on Sunday 05 April 2015. This late 2009 model iMac was provided to me last year thus it had five years of build-up including mine when I began to use it till I did what I will outline below. Sure, the user account was completely obliterated via Users and Groups, but the select lot of us know Mac OS's digital trails from yesteryear were clearly visible if one knew how and where to search. Reinstalling does some serious good for a machine in such a scenario. Below is an outline of the process I used with nothing but successful success. Folks may disagree with some of it but thus far nobody has outlined their process. If you do not wish to read this is not for you.

Step 01: CLONE the source volume
Before you do anything, it is wholeheartedly recommended you clone – not back up, synchronise, copy et cetera the current iteration as it is of the primary operating system in use. By a clone I mean a fully working bootable clone complete with the Recovery HD partition. I personally use Mike Bombich's Carbon Copy Cloner to successfully accomplish this [stay tuned for the MUCH improved version 4.1]. The particular schedule I set up states the following:
• a full clone will be ensured with incremental updates every four hours;
• volumes will be verified using strict volume identification;
• corrupted files will be found and replaced;
• root-level items will not be protected;
• items, if any [which is never in my case], will be excluded;
• SafetyNet is off thus a deletion pass will be performed if required space is insufficient
That is how I do things and I know others – especially average every day users will never delve nearly as deep into the software. I mentioned the Recovery HD partition above and the relevant setting for that is located on the General pane in the preferences window. When the cloned operating system is ready for live production, test it because it will be what you will use for the next two days if you follow my process exactly as I explain it aside from the particularities of my Carbon Copy Cloner task schedule.

Step 02: boot from the clone and permanently destroy your primary operating system
Now that your fully operational bootable clone is just that – fully operational, it is time to have some fun and give yourself some piece of mind. Well, at least it was fun for me. I could have used BCWipe but I chose to travel the easy route and use Disk Utility to perform a seven-pass wipe on the entire primary hard disk. Mine is 1.82 TiB so the entire task took days to complete. The passes are unable to be customised or verified but it should suffice. It is wholeheartedly recommended you wipe the hard disk because to simply reinstall Mac OS on a newly formatted disk does NOT make the installation any more “clean’; it only makes it so to both the user and operating system. The remainder of what was still is if you or another knows how to recover the data. A single pass is a joke and so is three. Seven is not foolproof but that is the maximum security setting permitted by Disk Utility

To do this, launch Disk Utility which is located in the utilities folder. To the far left is a table of both the disks and volumes. The disks are always before the encompassed volumes. Select the source disk – NOT the source volume. You are using the clone so to destroy the source is okay. Navigate to and select the Erase tab [there should be five]. Navigate to and activate the Security Options button then move the slider to 100% and save the changes. If you wish to rename the volume Disk Utility is about to erase navigate to the text field which is to the left of the Erase Free Space button and enter what you wish. Navigate to and activate the Erase button located to the right of the Security Options button. As I recall, a warning dialogue appears which states the disk will be formatted and repartitioned. I assume since you are advanced enough to reinstall Mac OS you are also advanced enough to know about partitioning and what type of partition scheme Mac OS requires, which is selected by default as is the file system. If the dialogue appears simply confirm the action and forget about this for an estimated thirty-six hours. It really depends on the computer's hardware including the disk being wiped.

Step 03: download a free copy of Mac OS from the Mac app store
Since the computer is running a fully operational [Internet included] clone, you can now download a free copy of Mac OS X 10.10.# from the Mac app store. To accomplish this, launch the Mac app store, press Command-F, type Yosemite, press Enter then press Tab till VoiceOver focuses on the Yosemite download button. Activate that and activate the Continue button if a dialogue appears which states Yosemite is already installed but continue to download a complete installation. I am badly paraphrasing but that is basically what it says. It will not appear immediately. The .app file is over 4.50 GiB in size and will be placed in the Applications folder.

Step 04: commence to installation
By the time you are ready to go forth from this step, Disk Utility should have successfully completed its seven-pass wipe of the source hard disk. There is no point to install a factory-released copy of Mac OS on a disk that has the current iteration of it entirely marked for deletion but just. Navigate to the Install OS X Yosemite file in the Applications folder, launch it, agree to whatever that is Apple Computer wants folks to read, select the disk that was just wiped and activate the Install button. Make absolutely certain you chose the correct disk because, if by accident you chose the clone,, that will be extremely problematic to say the very least. From the moment you activate the Install button everything is self-explanatory. I did it with much ease and you should likewise. When the system reboots it will [obviously] do so into the to-be-installed operating system. It is imperative to remember the installer – the source copy of Mac OS that is being installed on the newly wiped disk resides on the clone. The clone MUST NOT be disconnected till the operating system has been completely installed and fully set up..

Step 05: FileVault
Yes, yes before anybody mentions it I will do just that. FileVault [technically FileVault 2] is not foolproof because Passware Forensics Kit of whatever its name is can defeat FileVault without even trying. Caveat emptor: Passware Forensics Kit requires physical access to the computer. Furthermore, the main downfall of FileVault is it only encrypts when the system shuts down – not sleeps… shuts down. Again, many believe this is not necessary but it is wholeheartedly recommended. Considering not much is on the disk if you are following this process encryption will not require nearly as much time as it would if you decided to enable FileVault after complete configuration and customisation has been accomplished. FileVault requires, without question, a working copy of the Recovery HD partition. This is okay because it was installed when Mac OS was installed. I think it is a very useful piece of information to know thus I mention it. To enable FileVault, launch System Preferences, activate the Security and Privacy button, select the FileVault tab, activate the lock button, enter your password if one exists, press Enter and activate the On button. The steps therein are self-explanatory. The time required to encrypt the entire volume depends on the hardware thus it may take a while. You can perform step 06 below whilst the encryption progresses. I suggest checking the progress once per hour to know just how fast the process is and also the estimated time.

Step 06: configure the fresh installation
Well after the freshly installed operating system is booted the installer can be safely [and preferably securely] deleted from the clone. Many folks may opt to restore items from the clone but I suggest simply to re-download all purchases from the Mac app store, and if possible, re-download all third-party software from their respective websites. Personally, I back up the latest versions of every worthwhile third-party app I use – including the Dropbox app itself – to my Dropbox account and maintain those with every app update [which obviously means an updated app, package or bundle]. The first app I installed was Dropbox which I obtained from the clone which has a copy of the Dropbox contents synchronised from the Dropbox website. The second app I added to the Applications folder, again from the Dropbox folder located on the clone, was 1Password because I must enable myself access to my highly secure vault to obtain my Dropbox credentials. The most up-to-date iteration of the vault was previously synchronised to Dropbox which was also copied to the new installation. Sure, I could simply have copied the Dropbox folder and all sub-folders [I am both obsessive and compulsive with organisation] but I chose not to. Once the Dropbox credentials were entered in the Dropbox app and the folder was synchronised, I copied all the apps to the Applications folder. Afterwards I went through the tedious process of re-activating each one via the license information also contained in my highly secure vault. All truth be told, I procrastinated till the operating system itself was ridiculously customised to my discretion. This applied to everything from System Preferences settings to both OnyX and TinkerTool System/TinkerTool's settings. Two of the very first apps I will always install after Dropbox and 1Password are Hands Off! and Little Snitch. If you do not have access to or wish not to procure sighted assistance simply bypass Little Snitch. Hands Off! will definitely suffice if you wish to use it. At the very least, enable the built-in joke of a firewall. Apple Computer is so overly confident with regards to the security of the Mac OS X operating system they included a primitive firewall but nonsensically did not bother to enable it. Perhaps you should take care of this trivial toggle before you enable FileVault as mentioned above. It is also recommended to enable the stealth setting via the Options button on the same tab [the Firewall tab is to the left of the FileVault tab].

That is the process I used to format, repartition, securely wipe, reinstall and reconfigure Mac OS X 10.10.#. Of course the seven-pass scheme is not foolproof but most people are not out for your disk's platters so it is safe to assume security. I really hope that helps not only the one who started this thread but anybody who wants and/or needs to do the same. If I can do it within twelve hours [aside from wiping the disk] you can too. I promise.

#3 format and reinstal

Well, I don't have important data on the build in drive, since its size is so small anyway. So I don't have to clone and all that. So do I understand correctly that if I open the installer after downloaded from the app store, will it reboot or will it just install over the current system. Should I not reboot the installer from the super drive? The file valt is good but a waste of time if you don't have really allot of data to secure.

#4 erase and reinstall

Member of the AppleVis Editorial Team

If you download from the AppStore and let the installer reboot, it will preserve your data. To erase and reinstall OS X, use the process described by the other commenters, minus the cloning if you don't have any important data. Start up in OS X utilities and erase your disk, called Macintosh HD by default, and then install OS X on your freshly erased volume.

#5 disk utility

So how do I start up in the disk utility without booting into the mac hd volume? If I use the command r on boot, it will do the recovery partition so I won't be able to format that then as well. And I stil don't know if the installer will boot when I open it, or will it be like windows where you can choose to start install from the currently booted system or if I have to boot into it, and I don't know if mac book pro will boot from the super drive.

#6 application selection table

Member of the AppleVis Editorial Team

When you first start up in OS X utilities, there is a table with four options, restore from Time Machine backup, reinstall OS X, get help online, and Disk Utility. Navigate as you would other tables in OS X and click continue to open it. From there, it should behave like the Disk Utility on your startup disk.

#7 RE: format and reinstal

To boot from a Super Drive you would need to first burn the installer to a dual-layer [greater than 4.37 GiB capacity disc]. However, this is not necessary. I suggested to create a bootable clone because, if you wish to completely erase the drive – including the Recovery HD partition and reinstall to that same drive, it is required for Mac OS to be booted from another drive – not partition. A very large flash drive should suffice. Yes, yes you can install over the current iteration of the partition as is currently and that will work; however, it will not be a fresh installation. There is no way possible to completely erase the drive and reinstall the operating system on the same drive whilst booted from the drive, and this includes the Recovery HD partition because the Recovery HD partition is, in fact, on that drive you are trying to erase. Installing Mac OS on a drive also installs the current Recovery HD partition so that will exist when installation is complete. I think it goes without saying partitions of any file system can not be modified when booted from the disk which contains those partitions. Partitions can only be added. I hope that clarifies things.

#8 booting from the super drive

Well, to make bootable USB drives, is complicated and not always necessary. Can I not burn it on a disk as iso as you would with windows and Linux and just boot into the thing? Much less work, how is the mac book pro boot settings? Will it boot from the super drive? I don't need a clone, really that is not the issue. I always start from scratch as I have my data else where to restore or to reinstall apps.

#9 RE: booting from the super drive

You can burn it but that will require a dual-layer disc because the .app file as a full installer is greater than 4.37 GiB which is the maximum capacity of a single layer disc. To boot from it simply hold the Option key when the start-up noise sounds and acquire sighted assistance to direct your left or right arrow key presses. The boot manager is beyond what VoiceOver can see because it loads before VoiceOver can. Come to think about it, I am unsure if a .app file will launch properly if burnt to a disc as an ISO image would. That is assuming the boot manager would recognise the disc. I have never burnt a .app file to disc thus I am not aware of how the boot manager will deal with it if at all.

#10 DiskMaker X

Member of the AppleVis Editorial Team

The DiskMaker X app allows you to make a bootable OS X installer. I would recommend using a USB drive over a disk if possible, as larger sizes of them are more readily available and also perform faster. You will need to download the OS X Yosemite installer from the Mac AppStore. Once you have the installer and the DiskMaker app, follow the prompts to make a boot disk. At the end, it will give you the option to automatically start up from it. From there, you can access the disk utility to erase and reformat your harddrive and reinstall OS X. Here's a link.

#11 disk maker x

Thank you so much for this. It seems very easy with this program. So the only thing for now to get just my head around is what is the difference between booting with command r to do all these tasks, against using this file from the app store? I understand if I update in future I would need to get the file from the app store, but if I would download yosemity now and make a bootable USB, against the command r on boot, what is the difference?

#12 boot disk

When you boot from your external drive, you are actually loading the entire installer. This means that it will take less time because it just has to read data off the external disk and install the operating system to your internal drive. When you press command r, you are taken into a recovery image. The disadvantage is that the recovery image has to download a full copy of OS X from Apple which could take a long time depending on your internet connection speed.

#13 Adding a few things

You can download it using the recovery partition, or you can install it by downloading it from the Mac App Store first, then burning a .iso file hidden in the app file you downloaded. DiskMaker X essentially does this, but I prefer to do it manually. In my case, it's faster to download it from the recovery partition after I have erased my Macintosh HD partition, as it also takes time to burn then start up from the DVD. IF you prefer to download the installer from a running OS X partition, I'd recommend using a USB flash drive since that's faster, but the difference really isn't worth writing home about.

Also worth noting is that if you do decide to use the recovery partition, connecting to Wi-Fi from the status menu may crash VoiceOver repeatedly. I do not know if Apple has fixed this finally, but it also does not occur on all computers. If you find that it crashes for you when connecting to Wi-Fi, do the following:

  1. Go to the Utilities menu with VO-M, then Vo-right until you get to it.
  2. Press VO-down arrow until you get to Terminal, then Vo-Space to open it.
  3. Once Terminal opens, type the following exactly as written and substitute network name and WIFI_PASSWORD for the appropriate settings: networksetup -setairportnetwork en0 Network name WIFI_PASSWORD
  4. Once you press return, you will be connected after a little while. Feel free to press Command-Q once this happens and proceed with the install.

Obviously if you do not use Wi-Fi to do this but use ethernet, disregard.
Keep in mind that you can actually start VoiceOVer when the process begins and your computer restarts, just give it a little while before you do so to make sure everything is running smoothly first. Although, I hear some people can't get VoiceOver on during the process. I didn't have that issue on my 2008 MacBook, 2011 iMac or my 2012 MacBook Air however. IF you can't turn it on, just give it a while. It can take a little bit.

#14 recovery partition

So if you use the recovery partition, and will it then stil be necessary to perform a bootable USB with the installer as you would if you did download it from the app store? Or will it install strait away from within the running recovery partition? Sorry its confusing, but I appreciate everyone contributions here to help a slow guy like me. I'm half way there at least.

#15 Recovery partition requires no bootable media


The recovery partition just straight up installs it for you once it tells you that it's about to reboot. Once this happens, you just wait until it reboots a few times.

If you don't format your disk first from Disk utility, be aware that it will instead upgrade your installation from a previous version. If you already have Yosemite on your partition, it will overwrite the installation but migrate your settings. If you want to have a totally clean installation, you will have to format it using Disk Utility from the recovery partition.

This method is a lot easier than bothering to make bootable media unless you need to install it on multiple macs or for some reason your recovery partition is failing. It is, however, rather useful if you do not want to use this partition and download it again if you have reinstalled before. In this case, though, you will probably have to install an update after the initial installation, so you can argue which method is faster in the end. There is no definitive answer on that. Also of note is that in most cases, wiping your recovery HD is not required. The recovery partition is updated either by updates through the App Store separate from OS X updates, or along with new major releases of OS X.

#16 Formatting more than tagging

App Developer

When you format a hard drive, you are NOT marking every file on the drive as ready for deletion. You are creating an entirely brand new file allocation table. This means that when you are finished with the format, neither the operating system, NOR the hard drive is aware of any previous files or their locations on the hard drive. Therefore, the hard drive continues to use the storage as though it were new from the factory. There is absolutely NO LOSS IN PERFORMANCE by re-partitioning and re-formatting a hard drive vs doing a 7 pass wipe on the hard drive and then re-partitioning / re-installing. Also, there is NO RISK of confusing your data with the "old data' thats on the drive, since that data has been orphaned and there is no way for the operating system nor the hard drive to accidentally stumble accross the old data and somehow be affected by it. No, the hard drive will simply plow right over any hard drive bits that it knows are available for use per the re-partition and re-format. So this notion that the old data somehow makes things "dirty" is complete rubbish. I defy you to find me any credible research done in this area which would suggest that a multi-pass wipe of a hard drive is in ANY WAY more beneficial to a user instead of just doing a re-partition / re-format - OTHER THAN THE INDENDED USE OF MULTI-PASS WIPES - which is to erradicate the hard drive of sensitive, or personal information, since a hard drive cannot be scoured by third party utilities and have its files re-assembled through special software once a multi-pass wipe has been done. But that is the ONLY benefit to a multi-pass wipe - the complete removal of private or sensitive files. (Notice that 7 pass wipes are referred to as DOD wipes - that is the Department of Defense) - why did they get involved in multi-pass wiping? Because they were concerned about a computers performance?  NO! So they could completely erradicate a hard drive of classified information (although highly classified computers get incinerated after the 7-pass wipe).In fact, that old data is so far removed from the computing environment, that in order to actually get to the data, you have to purchase special software that utilizes special non-standard commands within the hard drive itself to go and read every single data bit on the hard drive, then look for patterns that match known file patterns and if it happens to see some of the magnetic bits organized in these patterns, the software can then re-construct those old files onto a separate hard drive. Notice it's not even possible to re-activate the files on the current hard drive because the files were NOT marked for deletion ... they were abandoned and left for dead.For those of you who remember using casette tapes, 8-tracks or reel to reels for recording and listening to music, remember that tapes had magnetic pieces laid out onto the tape and as the music played it would vibrate the magnet in the heads and those magnetic fields would re-arrange the bits on the tape which could then run back over the same head and listen to the music you just recorded. Now remember it used to be advantageous to use an electromagnet to erase your tapes before recording over them again. This is because over time, the magnetic bits became more stubborn and more difficult to rearrange so that if you recorded music over previously recorded music you may sometimes hear the old music very faintly in the background. Hard drives are far more Advanced than cassette tapes machines, so when a hard drive abandons previously recorded data it will go back out and use those magnetic bits again as it needs to without ever hearing about or seeing or knowing anything about the previously written data.Therefore, when it comes to just every day computer usage , your system will run like it did when it was new witth a simple re-partition and re-foamat of the hard drive followed by a reinstall of the operating system. And the process of partitioning and formatting is mere minutes compared to meree DAYS or WEEKS doing a 7 pass wipe. It blows my mind how much time people waste because of simple ignorance which could be eliminated completely with a litlle knowlede and understanding of how things work under the hood.Just to re-iterate where the poster of this thread is completely wrong, the data is not merely "marked for deletion" when you perform a re-partition and a re-format, the data is literally orphaned, and is no longer real to the operating system ... its not been marked at all because its technically not even there, since all of the previous indexing records were wiped clean and created new from scratch ... its just a bunch of magnetic bits on a spinning platter that are arranged in weird patterns that have ZERO impact on the usage of that hard drive. So a muli-pass wipe is simply WAY OVERKILL and COMPLETELY UNNECESSARY!!!

#17 Create a bootable thumb drive

  1. Create a bootable thumb drive. I have a written guide somewhere, however if i never end up getting to it googling for the stuff at cult of mac should help
  2. . Boot in to it by choosing it in the start up pain under system prefs.
  3. Turn on voice over.
  4. Go to disk utility and reformat the whole entire drive. If ouhave boot camp it will hose it to.
  5. reinstall osx by choosing this option after quitting the disk utility
  6. Follow the prompts. and play the hury up and wait game.

good luck.

#18 RE: Formatting more than tagging

Ahh… makes me want to take out my cassettes and relive the times when music was ‘good’ and when folks appreciated the warmth and essence of analogue media.

I never wiped my drives for performance reasons because re-partitioning and re-formatting is sufficient for that. I did it due to privacy and sensitivity concerns. There is one person who I know is the owner of an extremely expensive forensics recovery machine [CEO of his computer business since the 1970s]. If that fails the only other method by which to recovery anything is to supply the drive to a company who messes with the physical platters according to what they told me. My recommendation to wipe using a seven-pass scheme is simply for the privacy conscious to attempt to thwart forensics-calibre or any other method of recovery. Nothing to do with performance.

#19 RE: Formatting more than tagging

App Developer

Makes sense,

I just have a thing when it comes to making sure people have the right information. I didn't want anyone to get the idea that they need to spend three days wiping their hard drive because they will somehow get better performance out of it. The majority of users out there can be fairly gullible where computer know-how is concerned, and sometimes it "feels" like ... if it takes a long time, it must be worth it - in the same vein as 'you get what you pay for' - kind of thing...

And yeah on the cassette tape thing ... I remember getting into chrome tapes that were denoted with a CrO2 symbol. My home cassette deck was chrome capable and my car deck was also chrome aware ... so I would record my CDs onto chrome cassette so as to almost eliminate tape hiss and it was real good quality ... but again ... reproducing digital masters to analog was not really true analog ... but I did lose my virginity to Pink Floyd The Wall listening to a chrome taped version from the back seat of my 1978 Ford Faramont with 6x9 Jensen speakers in the rear, some generic deck, and a 10 band EQ. The acoustics in that car were simply amazing. The trunk space somehow matched those Jensens perfeftly. I have yet to have a car with audio as clean sounding as that one sounded ... good times! ;-)


#20 RE: Formatting more than tagging

No doubt. In passing, I met gullible folks with regards to computer know-how and also who and what is in the streets. I think the feels-like illusion is a placebo effect of sorts which in itself can be a powerful and convincing thing.

Oooh… chrome tapes. I think they were manufactured in Japan. They are still available if you know where to look. The digital-to-analogue thing is amusing. I am a self-proclaimed audiophile, and though Pink Floyd is not my cup of Khool-Aid I would definitely sample that set-up [but sterilise the seat first hahaha]. Now I have to research if my Tascam tape machines are Chrome-aware.

#21 RE: Formatting more than tagging

App Developer

Usually the decks had a switch on them for chrome use ... there were usually two "depths" of chrome settings the second reducing even more hiss than the first, but if your source signal wasn't strong enough, you risk losing some of the audio. It is my opinion that the decks introduce a filter into the audio stream. The reason I think this, is because when listening to the headphone port while the deck is in record mode, the reduction of hissing happens in real time, and there is a noticeable difference between settings 1 and 2 on the chrome switch. There's no way that the you would be somehow listening to the tape playing back through the heads as it is simultaneously recording from the source, so the logical conclusion is that each of those switch settings introduces a filter of some kind ... I don't know if you'd call that a hi-pass filter or not ... I think that might be what it is since it takes out the high frequencies of hissing while attempting to maintain the desired audio in that frequency range as many instruments would produce sound in the hissing range.

However, I never did try those chrome settings on a non-chrome tape to see if there was any noticeable difference.

Concerning analog vs. digital ... I really never understood the apprehension to adopting digital since the number of samples in a second of music far exceeds what our ears are capable of discerning, and the frequencies that are sampled are also outside the range of normal human hearing. So in essence, the only real difference between analog and digital recordings, would be the lack of analog artifacts which are common in the media (tape hissing, vinyl pops through needle friction etc.) ... Digital would be able to represent the sound exactly as it would be expressed by whatever analog device received it whether that be a mic element, or a piezo pickup ... once the analog wave is converted into electrical energy, a digital sample will be indistinguishable from what you would hear if you were sitting at the mixing board during the recording process.

What absolutely amazes me, is that they actually had media capable of storing 600 megabytes back in 1986, when the best computer you could get could store at best 360k (.36 megabytes) on a 5.25" disk. And they only had to charge $15 for CDs ... that would have been 1,800 floppy disks on a single CD ... that is impressive! And people still use CDs today ... it's probably the only media type that has survived almost 30 years so far and is still used at a level where you can go to walmart and buy them without special ordering them. Find any media type that has survived as long.... well ... outside of vinyl I suppose ... ;-)


#22 off topic about tape decks

I hate to call attention to this, but I think the comment about tape decks and what not was a bit more than of topic. Could we please try to stick to the topic as stated by the title of the post? I know i'm not an admin, but wow. Not trying to be rude, but there you have it.



#23 OT

App Developer


#24 No worries

No worries. Happens to us all. Just thought I'd kinda point it out since it didn't really fit with the topic of the thread. :)

#25 Less is More...

Member of the AppleVis Editorial Team

In forum moderation, sometimes less is more. That is, there are situations where you decide the best approach is to leave things alone.

While the discussion of tape decks was indeed very off-topic, in this case the topic had been inactive for 3 days...and it was our hope that that would be the resolution of the issue.

For what it's worth, users wishing to discuss anything off-topic privately may certainly do so using the "Contact" link on the respective user's profile page.

#26 Reinstall Mac Yosemite

Note: - Before you reinstall Mac Yosemite, you must be connected to the internet.
Now, to restore Yosemite from a Time Machine Backup, you should:-
1. Restart your Mac and immediately hold down the Command and R keys (once you hear the startup keys).
2. Now, a recovery windows open. Here, select the option to restore from time machine backup.
3. Select the backup disk of your time machine.
4. Select the time machine backup, which you want to restore.
5. Click continues and follows the screen instructions to process further.