My Imac keeps crashing, and I can't work out why
Hello everyone,
I did try and see if I could find similar questions, but keywords like "black out" and "crash" brought up threads that were years old. Apologies if this has been asked before.
As the title says, my iMac keeps crashing. It's not doing a kernel panic (I have seen those a couple of times, so I know roughly what I'm looking for). With this, there are no words or anything - the computer just dies. Everything is fine, and then boom! Black screen. It restarts on its own, and then sits waiting for a password to sign back in.
Details about the Crashes
It doesn't seem to be 'tied' to an activity. The computer has crashed while I am away, and while I've been using it.
Even comparing 'unattended' and 'attended' crashes, there is no discernible pattern to why it dies. With the unattended crashes, time doesn't seem to be a factor. Sometimes I'll be gone for an hour and it hasn't restarted, while other times I'm only away for a minute or two making a cup of tea and it's black-screened and restarted. When I'm using it, I've had it crash while I'm watching Youtube, actively typing (Reddit messages, Facebook, Pages), and when I've been in the middle of reading a webpage.
The crash process seems the same. It black screens, the fans whir down, and then the computer restarts. It goes to a grey screen with a black Apple logo and a black loading bar, and - after loading - it goes to the normal password login screen.
The only thing I have noticed is that the computer almost always seems to have reset overnight while I'm sleeping. Not only that, but it will usually need three or four cycles before it settles. So what I mean is, I come down and power it out of sleep mode, and it's crashed overnight. I sign in, it'll sign in, crash and reboot. I'll sign in again, same. Sign in again, same. And then, usually I'll sign in again and it will work.
Sometimes it can crash half a dozen times in the morning, occasionally it doesn't crash. The other crashes happen sporadically through the day - sometimes not at all, but usually two or three times in a day.
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Stuff I've already tried
This has been going on for some weeks. Obviously I have tried to fix it, but I haven't had any luck.
So far, I have:
- Reset the PRAM.
- That got the computer to 'chime' again on start-up (which it had stopped doing), but otherwise nothing changed.
- Reset the SMC.
- Nothing.
- Booted into the diagnostic mode, and did a check of the hardware.
- That came back clean. I will admit, I only did the 'short' version. I had something I needed to get done, and didn't have time for the hour the Mac was saying a long test might take.
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Computer details
I know you'll need the specifications of the computer, so I'll give that to you now.
Reading from the About My Mac overview, it is a Mac 27-inch, Mid-2011.
Processor: 3.1 GHx Intel Core i5
Memory: 4GB
Startup Disk: Macintosh HD
Graphics: AMD Radeon HD 6970M
Also, I am using OSX Sierra, 10.12.6. I had been on an older version, but the computer kept popping up alerts demanding I update, and I eventually relented. It actually wanted to install High Sierra, but then said that it couldn't.
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Please help
As I said, I have tried everything I can think of to fix this. Various searches suggested it might be the PRAM and SMC, but resetting them didn't help. Then, I thought it might be the power supply, but when I checked the hardware diagnostic nothing came up. So I'm stumped.
I love the computer, and I had been intending to install more RAM into it. If I upgraded the RAM, I think I could keep using it for years probably - I don't particularly need anything more powerful, at least for now. But I don't want to spend money on new RAM just for the whole thing to (permanently) die on me in a month.
Would going back to an older version of OSX help? Is there something else I can try? Do I need to do a longer hardware scan in the diagnostic mode to check the power supply? Would sacrificing one of my siblings to the Dark Lord help?
Please let me know if there is anything I haven't done, and should try.
Thank you.
iMac 27″, macOS 10.12
