Q: Freezes and screen won't turn on after shutdown
Hi,
I'm having a lot of trouble with my iMac Retina early 2015, and I can't figure out what's wrong with it. The problem is if I use the mac for a period of time, sometimes it can be almost a whole day other times it can be a hour. It all of the sudden freezes completely and the only way of getting it to work is to do a hard shutdown (holding the power button until it turns off).
But when I try to turn it on back on the the screen won't turn on. And I have to again do a hard shutdown, sometimes it takes around 5-6 times before the screen turns on. And if the problem occurred once and I try to use the Mac immediately after, it freezes within the first 10 minutes, and the whole procedure has to be repeated for another 10 minutes of usage. The only way to get it to not freeze up is if I don't use it for like a day, but that still only gives me around 3-4 hours before the problem occurs again.
I sent it to a repair shop to get it fixed, I figured that maybe its the hard disk. They ran some Apple test and told me it's not the hardware but the software causing the problem. So they factory restored it and gave it back to me. But it didn't fix the problem.
Any thoughts on what could be the cause of this?
iMac with Retina 5K display, OS X El Capitan (10.11.2)
Posted on Dec 22, 2015 3:28 AM
Either the graphics processor or the logic board is faulty and will have to be replaced.
Make a "Genius" appointment at an Apple Store, or go to another authorized service provider. You may have to leave the machine there for several days.
Back up all data on the internal drive(s) before you hand over your computer to anyone. There are ways to back up a computer that isn't fully functional—ask if you need guidance.
If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you have at least two complete, independent backups, and you know how to restore to an empty drive from any of them.) Don’t erase the recovery partition, if present.
Keeping your confidential data secure during hardware repair
Apple also recommends that you deauthorize a device in the iTunes Store before having it serviced.
*An SSD doesn't need to be zeroed.
Posted on Dec 22, 2015 8:23 AM