2015 iMac crashes or hangs waking from sleep

[kahlil88]

Trying to fix an iMac for a client. Computer is VERY slow to resume from sleep mode (blank screen for maybe a solid minute) or kernel panics and reboots. Customer also reported programs and files won't open. My initial suspicion was a buggy or incompatible SSD, but I've had no success with a brand new WD and even tried a clean install of Catalina, thinking it could be a Monterey bug. Running a memory test overnight for good measure but this thing is driving me crazy and I'm running out of ideas.

 

[Street28]

Did you have any joy with this?

I've having exactly the same problem with a 2015 iMac here. About a month ago, I upgraded the 1TB hard drive for an SSD and I've just had it brought back to me as it's crashing when waking from sleep.

I've seen the older iMacs have issues with NVMe drives, but this one didn't have a Fusion drive and can't see anything about incompatible SATA SSDs. I was just in the process of backing it up to do a clean install to see if that sorts it.

The drive health looks OK and the SMART stats are good and it's on the latest firmware as well.

 

[kahlil88]

No luck. I'm familiar with the NVMe issue, which is what I thought was going on initially. Last time I ran into that issue, there was an easy workaround involving the sleep/hibernation settings but it didn't make a difference with this computer.

It also frequently gives the "your computer was shut down because of a problem" when booting up after a proper shut down. Even with sleep disabled, the screen takes abnormally long to turn back on.