My iMac starts up normally but after a few minutes the screen goes black. All other functions continue normally including an ongoing FaceTime chat.
iMac 27″, macOS 10.13
First try resetting the NVRAM and also restarting in Safe Mode. Please report back with results.
First try resetting the NVRAM and also restarting in Safe Mode. Please report back with results.
I don't think I have these third-party apps. The problem syarted a couple of days ago, when the screen went black after about half an hour of use. Since then the "live" time has got progressively shorter--now a few seconds. My guess was that it was a temperature sensor malfunctioning. In any event it looks like a hardware isssue.
Yea' it could be over heating. Shutdown disconnect the power cord, vigorously vacuum out the bottom air intakes, blow compressed air into the rear upper vents and repeat. Then plug it back in and test it.
I tried vacuuming all the vents but it didn't help. I hve taken it in to our IT people. It seems the video card is shot--apparently a common problem with this vintage iMac. It's too old for parts to be available, so the "cure" is to buy a new machine.
Thank you all for your suggestions.
This didn't seem to help. The screen is now going black/blank a few seconds after the computer is turned, which doesn't leave much time to try things.
Do you have any third party antivirus, cleaning or any other third party "maintenance" apps installed?
So you can see your startup screen for a few moments?
If it doesn't stay lit-up in Safe Mode, then I would suspect that is has a hardware issue which needs to be checked out by an Apple Store or Authorized Apple Service Provider.
Sorry that didn’t help.
You’re welcome.
Screen goes black
