I have 2015 Macbook Pro running High Sierra. At the end of the day I put it to sleep (I run SuperDuper which then puts it to sleep).
In the morning, I’ll tap on the keyboard to awaken it.
Some days, I see my usual gray background screen with the login box. Other days, however, I see the standard High Sierra screen (out of focus colors, etc.) with a login box. I normally only see this screen if I’ve restarted.
So, is my machine secretly rebooting itself in the middle of the night? Any idea why?
Launch terminal.app and use the uptime command which shows time since boot.
Last login: Tue Feb 8 08:54:13 on ttys000
usename@Machine ~ % uptime
8:54 up 5 days, 16:26, 2 users, load averages: 1.62 1.62 1.72
username@Machine ~ %
Hmmmm, says 14 days, so it didn’t boot last night (I saw the High Sierra screen this morning).
I wonder why sometimes it awakes to a gray screen and sometimes to the High Sierra screen?
I’m thinking you might see the login screen when you’ve, well, logged out. So it doesn’t necessarily indicate a reboot, as your uptime stats confirm. If I’m right, then of course that just changes the question into “Why is my machine logging me out overnight sometimes?” Not sure how helpful that is (if at all), but there’s my $0.02.
I wonder if the Mac is hibernating? The return from hibernation is different from waking from sleep. (Though I thought you needed to press power to return from hibernation, so maybe not?)
Hmmmm, I was not aware of hibernate mode. I’ll have to read up on it.
The odd part about this is it’s irregularity. Sometimes I wake to the High Sierra screen, sometimes not.
Also, sometimes waking can be done by tapping the keyboard and sometimes that’s ignored and I have to actually open the lid (I have it set up with the lid closed attached to an external monitor and keyboard).