Does Time Machine back up the operating system or just the data on the hard drive being backed up?

Question

Does Time Machine back up the operating system or just the data on the hard drive being backed up?

I've completed a Time Machine backup of my MBPro Retina's hard drive. I want to go back to Yosemite as Sierra is crashing several of my Applications and plug ins. The problem is the GeForce 650M video card is not playing well with Sierra and there is no solution to date.

What I'm unsure of is whether Time Machine will reinstall Sierra on my hard drive once I wipe clean the current laptop hard drive and install Yosemite? I'd then transfer the Time Machine backup to the Yosemite OS, provided Time Machine doesn't reinstall Sierra.

MacBook Pro with Retina display, OS X Yosemite (10.10.3)

Posted on Oct 16, 2016 10:26 AM

Reply

Answer 1

léonie

Level 10

202,245 points

Oct 16, 2016 10:32 AM in response to leicaman94044

See this support document: macOS Sierra: Revert to a previous macOS version

https://support.apple.com/kb/PH25593?viewlocale=en_US&locale=en_US

Reply

Answer 2

Oct 16, 2016 10:45 AM in response to léonie

léonie,

I don't have a backup in Time Machine from my previous OS. I only backed up my laptop's hard drive using Time Machine once I started experiencing problems with Sierra.

My previous OS was Mavericks... but I'd like to install Yosemite as another laptop I have is running Yosemite with no issues.

So the question is as follows: how do I delete Sierra and install Yosemite... and then use my Time Machine backup (again, made when I was running Sierra) to get my data installed in the Yosemite OS?

A step by step process is what I need as I've never done this before.

Thanks for your assistance.

Reply

Answer 3

léonie

Level 10

202,245 points

Oct 16, 2016 10:57 AM in response to leicaman94044

Did you save a bootable installer for Yosemite, when you originally installed it? Otherwise it will be difficult to revert to that system, if you did not make a backup at that time.

Which is the system your Mac has originally been released with? If you boot your Mac into Internet Recovery, you can reinstall the system your Mac has originally been delivered with, see this page: http://www.idownloadblog.com/2016/02/25/how-to-start-up-your-mac-in-internet-rec overy-mode/

Afterwards you can restore your apps, documents and data from your Time Machine drive.

Reply

Answer 4

Oct 16, 2016 11:05 AM in response to léonie

Thanks Léonie,

I never installed Yosemite on this laptop. It's installed on a different MBPro that I use when I have problems with this early 2013 MBPro Retina. I think (but I'm not sure) that this early 2013 MBPro came with Mountain Lion. I don't have a bootable installer for any OS with me... so I'll need to boot my Mac into Internet Revovery, reinstall the original OS and then upgrade to Yosemite.

So I'm assuming by your response that when I reinstall my apps, documents and date from my Time Machine drive I won't be reinstalling Sierra? The backup was made using Sierra and I want to make sure that I don't go through all the reinstallation steps only to delete Yosemite and reinstall Sierra.

Reply

Answer 5

léonie

Level 10

202,245 points

Oct 16, 2016 11:26 AM in response to leicaman94044

So I'm assuming by your response that when I reinstall my apps, documents and date from my Time Machine drive I won't be reinstalling Sierra?

Right, you install an earlier system by booting into Internet Recovery, and when your Mac first launches after the reinstall, you use the Setup Assistant to restore your applications, settings, and the documents and data from your Time Machine backup. The Setup Assistant will ask you what you want to restore from your Time Machine backup.

Reply

Answer 6

Oct 16, 2016 11:27 AM in response to léonie

Thank you Léonie. I appreciate your answer.

Reply