IMac Freezing and rebooting

[Velvis]

Client has a iMac that frequently crashes with a white screen and either reboots on its own or needs to be rebooted.

Hardware test says all is fine. Apple Store said it failed the video test once but after that it passed.

I tried cleaning up old software and then tried a new user profile.

Also tried updating the OS to the latest version.

I was unable to reinstall the OS while keeping the data in place. Gave me a error that Google pointed to the date being wrong but that wasn't it. Further investigation seemed to indicated that the current OS wasn't the original OS and so it couldn't do it.


Anyway, Still the problem remains.

I have a time machine backup.

I would like to wipe the drive completely reinstall the latest version of OS X and see if the problem goes away. (Which would then point to a hardware issue)

My concern is this:

What does time machine backup? Can I recover just the files and not the old os install? (I don't want to reinstall the existing problem)

I am not super familiar with Mac's like PC and I don't want to lose data.


Thanks for any tips.

 

[Markverhyden]

What model?

Time Machine is not just one backup. It's over time. So you should have numerous restore points. And do not assume that the TM restore points are trouble free. While it's rare, I've had several instances where the TM stores were corrupted because the HD had problems. Many times nothing can be recovered.

What did you do to try to reinstall the OS?

Some iMac series do have issues with video, etc chipsets. But your symptoms also happen with HD problems.

My action plan would be to hook up a USB/Firewire/Thunderbolt external drive. Boot into recovery mode and do a TM restore to the external drive. Using the Option key boot into that install and let them use that for a while and see what happens.

 

[trevm999]

You can use migration assistant with the time machine backup to transfer everything back in after installing the OS. I've rarely ever done that though, I always made my own backup.

 

[BigFu]

To answer your questions:

What does time machine backup?
Everything, including the OS, apps and data.

Can I recover just the files and not the old os install?
Yes, using migration assistant.

What model/age iMac is it?

If you do use migration assistant to copy the data across use a USB 3.0 ext disk to create and restore from. I recently did this over wifi using a Time Capsule with roughly 350GB to transfer and it took about 7 hours.