Hi all. Wondering if anyone has advice or suggestions. I have a 2011 iMac that I use as a home server of sorts. I have it set to never go to sleep, but I have the display set to sleep after 15 minutes. I've run it like this for months without issue but lately when I move the mouse to wake the computer the machine reboots. It goes from a dark screen and the next thing I see is the grey startup screen. Reminds me of a kernel panic. Once or twice it's gotten caught in a boot loop. The desktop loads up and boom, reboot. A few times it never even got that far. Others it got a little farther. I found that if I unplugged my USB hub and thunderbolt drives the boot-loop would stop and it would run normally. While not super convenient, I decided to run without those for a while. But it happened again. So I re-installed High Sierra. (10.13.6) I just did a re-install over the system. I ran the updates as needed. I did a clean install onto an SSD a little over a year ago, and I don't use the computer much, so I've kept it mostly clean of extra apps, though it has a few syncing programs and other utilities. (Sync.com and Google Drive) It seemed to be working again, but tonight it just rebooted on me when I grabbed the mouse. I'm suspicious that the machine is actually going to sleep, despite my settings, because it takes so long to wake up sometimes. When the machine reboots I usually don't see a "this machine shut-down unexpectedly" window. I don't know if that got deprecated or not, but I'm not seeing it. Tonight I installed Amphetamine and told it to keep the machine alive indefinitely, but allow the display to sleep. I'll see if this makes any difference. Has anyone had similar experiences or ideas for things to test? Thanks a bunch.