- Joined
- Feb 1, 2011
- Messages
- 4,428
- Reaction score
- 2,144
- Points
- 113
- Location
- Sacramento, California
Here ya go.
This is different than what most of the articles on the Web suggest doing. It requires that you have a clone external backup of your internal hard drive. But you should probably have one of those in any case. (I can explain why in detail, if someone wants to start a backup plan thread.)
- Download the latest version of the MacOS to your startup hard drive (that is, your internal hard drive). (It's important to do this first.) It won't show up in your downloads folder, rather it appears in your Applications folder. It will be called e.g. "Install Sierra."
- Make a bootable clone of your startup drive (that is, to an external hard drive). I use SuperDuper (free/$28) for this:
http://www.shirt-pocket.com/SuperDuper/SuperDuperDescription.html
CarbonCopyCloner is also popular. You can even use Disk Utility to create a clone for free, but it's much slower than SD or CCC.
- If your internal drive is your work drive, and you want to be extra careful with your invaluable files, you may want to make a second clone on a second external hard drive, or you may want to make a versioned backup (e.g. Time Machine), or you may want to do a backup to the Cloud, or a combination of these.
- Boot (startup) from your clone (that is, your external drive that you created a clone on). (You can do this by setting your external as your startup disk in System Preferences.) *MAKE SURE THAT THE CLONE IS PERFECT IN EVERY WAY* Once you are sure that the clone is perfect, use the copy of Disk Utility that resides on your clone to erase your internal hard drive. Make sure that you set things so that your now blank internal hard drive has one partition, uses the GUID partition scheme, and that it is set up as Mac OS Extended (Journaled).
<http://www.macissues.com/2014/04/05/how-to-prepare-a-drive-for-use-in-os-x/#more-657>
- Use the MacOS installer on your clone to install the MacOS on your internal hard drive. During the installation (towards the end), the MacOS installer will ask if you want to move data from another source onto the drive on which you are installing the MacOS. It will give you several options for what you
want to move over. Have it move the data you want from your clone onto your internal drive.
That's it. You need to set aside the time to do this. Depending on how much data you need to move over it will take up to a few hours.
One big tip. Make sure to give your internal hard drive and your external hard drive two very distinct names that make them dead easy to tell apart. Because if at any point in this process you get confused and you designate the wrong drive for a particular action, you will have truly screwed yourself.
Big tip number two. The MacOS installer deletes itself after it installs the MacOS. So, if you intend to upgrade several Macs, it's a really good idea to make a copy of the MacOS installer and stash it somewhere before upgrading, because you probably don't want to go through that long download again. A copy in another folder works fine, as will putting a copy on an 8GB or larger USB flash drive.
Some folks like to manually re-install all of their applications as part of a clean install, rather than have them moved over for them by the Installer or Migration Assistant. Some even insist that it isn't a "clean install" unless you do this. You have to decide for yourself if you feel this is necessary. I don't think that it is, but doing it manually certainly gives you the opportunity to take stock of which applications should be updated for the version of the MacOS you are upgrading to. Here is a database of which apps are compatible with various recent versions of the MacOS:
http://roaringapps.com/apps
