OS X Yosemite is seriously watching you and you have already checked the compatibility of your applications. So all you have to do is start to install it. Only downside, you would like to do a clean install, or a “clean install” as we say in the middle, and you have absolutely no idea how to go about it. No problem, the whole procedure will be explained in full, in width and across in this tutorial.
Basically, to install OS X Yosemite, all you have to do is start the Mac App Store and start downloading the application made available to us by Apple. She will take care of everything for us, and who will take us by the hand to install the update on our machine.
This method is obviously the easiest, but it is not necessarily the best because it will not fix any problems you may be having with your Mac. If it tended to plant before, it will do so after too. It is precisely for this reason that the “clean install” is increasingly popular among apple eaters.
And for good reason since it allows you to start from scratch, a bit as if we had just taken our Mac out of its prestigious box.
Which Macs are Compatible?
But before going any further, be aware that Yosemite has not been compatible with all Macs since the dawn of creation.
If you want to enjoy it, you must have a 2007 or newer iMac, a late 2008 or newer MacBook, a late 2007 or newer MacBook Pro, a 2009 or newer Xserve, a late 2008 MacBook Air or newer, an early 2009 or newer Mac Mini, and an early 2008 or newer Mac Pro.
If you don't have all that, it's fucked up, all you have to do is curl up in a ball under your desk.
Back up your data
The first thing to do before you start is of course to back up your data . If I put this expression in red, in bold and underlined, it is not by chance because the “clean install” will remove everything which is on your boot disk.
The system, of course, but also your applications, photos, videos and documents.
What does it mean ? Quite simply that you will have to put them aside to find them more easily later. There are obviously several methods to carry out this operation, each with its advantages and disadvantages:
- Backup to Dropbox, Google Drive, iCloud and so on: There, it's simple, you send all your files to the “cloud” and you can then find them from your brand new Mac without any problem… on the express condition of show you very patient. If you have a bad connection and a lot of data to process (I do), then synchronization may take … several days.
- Backup with Time Machine: This is the simplest solution because the tool is directly integrated into the system and you will therefore have nothing to install on your bike to enjoy it. Be careful, however, because you will still have to think about investing in an external hard drive, or even in a NAS to benefit from it in the best possible conditions. But that's not his biggest flaw. No, the problem with Time Machine is that it also backs up user preferences and applications. With all the bugs and instabilities associated with it.
- Use another solution like Carbon Copy Cloner: If I quote this application, it is not for nothing because it is undoubtedly the best of its kind. It is indeed very effective and it will allow you to finely control the way your backup will be made. Be careful, however, because all is not perfect and the tool ultimately has two drawbacks. The first is that it may quickly discourage neophytes. The second is that it is not free and you will have to pay 34 € to take advantage of it.
- Make a manual backup: The last method is probably the least obvious since it consists of making a manual copy of all the files that are important to you. The only thing you will need is an external hard drive or a NAS. Then, well you will have to go find each file, each folder and copy it to your backup media. The trick, of course, is that you should make sure that you haven't forgotten anything before starting the installation of Yosemite.
There may be other methods, other ways of doing it, but you will already be spoiled for choice with those. Note that you also have the possibility of combining several.
Personally, I store all my files on my Dropbox. My Google Drive is used to make copies of all documents relating to my business. Behind it, I obviously make backups to my external hard drive, while my NAS allows me to store (and redistribute) my media across all devices on my network. And especially my television, thanks to Plex.
If you know any other tips, or if you have any advice to give as well, the comments are obviously there for that.
Create a bootable usb stick with OS X Yosemite
Now that almost everything is ready, you can get to the heart of the matter and start the download of OS X Yosemite from the Mac App Store.
And then, well, we'll have to… wait. And for good reason because the file in question is a little over 5 GB and the company's servers are obviously very busy. So you have time to go take a shower, and drink your umpteenth little morning coffee.
The installer will start immediately. You won't have to worry about it, just close it , or minimize its window. Your goal now is not to install Yosemite but rather to create a bootable usb key which will allow you to carry out this famous “clean install”.
Without it, it will be impossible to continue.
So you will need two things:
- A large capacity usb key (8 GB or more).
- Time and patience.
There are several ways to create a bootable usb drive. The simplest method is finally to go through the Terminal but you can also choose to rely on the disk utility.
Building on the Terminal
Start by taking your USB key and then plug it into one of the ports on your Mac. Take care to save the contents if necessary. Then change its name and go for something easy to remember, like “XXXX” for example. How? 'Or' What ? By going through the Finder (right click then rename), or by formatting it using the disk utility.
When everything is in order, open the “Applications” folder, then the “Utilities” folder and launch the Terminal immediately.
Then swing the following command line, like a brute brute:
sudo / Applications / Install \ OS \ X \ Yosemite.app/Contents/Resources/createinstallmedia --volume / Volumes / XXXX --applicationpath / Applications / Install \ OS \ X \ Yosemite.app --nointeraction
Simply replace the “XXXX” with the name of your key. Then validate the instruction by pressing the “Enter” key on your keyboard. The Terminal will ask you to enter your password. Do it and validate again.
The operation will start. You will have to be patient once again. When everything is finished, the Terminal will display a magnificent “Done” and you will only have to go to the next step.
Relying on disk utility
Are you afraid of the terminal and command lines? Do you prefer to use your field mouse than your keyboard? No problem, you will also be able to create your bootable key using the disk utility built into OS X.
Start by going to the “Applications” folder and right click on the Yosemite installer. Which is subtly called “Install OS X Yosemite”. Look for the option “Show package contents” then open the “Contents” folder before going to the “SharedSupport” directory. There you will find a file named “InstallESD.dmg”. Launch it to mount the disk image corresponding to the new version of OS X on your desktop.
The procedure may take a few seconds while your system performs the usual checks. Needless to say, we'll have to let it happen.
Once the image is opened, you will find that it contains only one directory. The others are hidden and you will have to run a command line to display them. Sorry, I promised you wouldn't have to get your hands on Terminal, but I lied.
For a good cause, then it doesn't matter.
Open the “Applications” folder and find the Terminal in the “Utilities” folder.
Simply paste the following line and press the “Enter” key to validate your choice:
defaults write com.apple.finder AppleShowAllFiles TRUE
There, well you will see magically appear a “.DS_Store” file, a “BaseSystem.chunklist” file and a “BaseSystem.dmg” file. You can therefore go to the next step and start the disk utility, which is also located in the “Applications” directory then “Utilities”.
Leave this window open.
Next, drag the “BaseSystem.dmg” file into the Disk Utility sidebar, under the “InstallESD.dmg” entry. Then make sure that you have your famous USB key, which should be called “XXXX” or something like that.
Click on the new entry you just created. In the right part of the window, you will see two fields appear: source and destination . The first must be occupied by the “BaseSystem.dmg” file. In the second, you will simply slide your usb key. Then all you have to do is click on the “Restore” button to start the operation.
A message will then appear on the screen, asking you if you are sure of your choice. Confirm by clicking on the “Delete” button. OS X will then ask you to enter the password for your administrator account. Do it and validate by clicking on the “Ok” button.
Wait quietly. At my house, the operation took six minutes. When everything is finished, your system will mount the key and it will open in the process a new window presenting its contents.
It's not over yet. Now, you will have to make the key bootable, so that it can be loaded by your computer when it starts up.
In the window that has just appeared, therefore, you will find a directory named “System”. Just go in and open the “Installation” folder. Delete the alias “Packages”.
Leave this window open.
Return to the “OS X Install ESD” window which remained open if you have followed this guide carefully.
Note: If this is not the case, you will have to go back to the “Applications” folder, right click on the Yosemite installation file, go to the “Show package contents” option, open the folder “Contents”, open the “SharedSupport” folder and launch the “InstallESD.dmg” file.
Phew, give me time to catch my breath.
Then select the “Packages” folder and drag it onto the other window, the one where we just deleted the damn alias. Wait for the transfer to take place. It might take a little while as our famous folder weighs something like 4.72 GB.
Go up in the tree structure of your key to the “OS X Base System” folder. Take the “BaseSystem.chunklist” and “BaseSystem.dmg” files from the “OS X Install ESD” window and drag them into this directory. Here again, we will have to wait a bit. When it's finished, you can close all those windows that are polluting your field of vision.
Now everything is ready. Admit it, finally, it would have been better to go through the Terminal, right?
So of course, here we relied on a simple usb stick, but you could have done the same with any drive, and even with your external hard drive.
Install OS X Yosemite
Rest assured because the hard part is done. The rest will not be a problem for you since you will simply have to install OS X Yosemite as we would with a simple wafer. The procedure is exactly the same.
Shut down your Mac and wait a few seconds to go get yourself a coffee. Yes again. Then connect your usb key to your machine. Directly to her. Don't go through an intermediary (hub, extension cord, stuffed dog), and be sure to unplug everything else.
Turn on your computer by holding down the "Option" key on its keyboard. Wait a few seconds, until a wizard appears on the screen. Using the keyboard arrows, move the cursor to your USB key, and then validate your choice by pressing the “Enter” key.
The OS X Yosemite installer will launch.
It will first welcome you and offer you to install the update directly. Disregard these instructions, and instead click on the “Utilities” menu at the top of the screen. There, choose the option “Disk Utility”.
The application will then launch. You will need to select your computer's startup volume from the list on the left. By default it is called Macintosh HD. On the right, click on the “Erase” tab and verify that the format is set to “Mac OS Extended“ Journaled ”. If all is well, click on the “Clear” button located at the bottom, to the right. It will ask you to confirm your choice by clicking a button again. Do it. From this point on, all the contents of your hard drive will be deleted. I really hope you've thought about backing up your data because it's a little late to worry about it now.
Wait a few minutes for the operation to come to an end. Count a quarter of an hour, unless you are unlucky.
Then go back by clicking on the "Exit Disk Utility" option in the application menu. The wizard will return you to the previous screen, and all you have to do is start the installation of Yosemite by clicking on the “Continue” button.
The wizard will then ask you to choose an installation disc. Take your beautiful, shiny new Macintosh HD and simply click the “Continue” button.
The wizard will start by copying the files necessary for the operation of the system. It will restart for the first time before continuing to install Yosemite. Then it will ask you to set your language and region. It will also allow you to connect to your WiFi network.
Yosemite will finally appear before your astonished eyes. It's over.
If you notice an oversight, or if you need more clarification on a step, the comments are there for that.
Bonus: Watch out for iCloud Drive
When you log in, Yosemite will ask you if you want to activate iCloud Drive. Be very careful because the latter is not compatible with previous versions of OS X, or even with iOS 7. If you have computers or mobile terminals that have not been updated, and if you want to keep all functions related to iCloud, then the migration will have to be refused .