Each night, at midnight my external disks eject.

[cupcakes2000]

That's it. Does anybody know why? Or what is causing this? At 0000 every day, they all drop out. (I get the errors about not unplugging disks). They remount instantly.

10.11.4 Beta (15E27e), though it's been doing it since 10.11.0.
2014 5k imac, high end.

Thanks

 

[DeltaMac]

Then, your external disks are not ejecting, but are disconnecting (for a moment)
Seems unusual that they remount without needing to disconnect the drives, or reboot....

Are they connected directly to your iMac, or do you have those connected to a USB hub?
What other things happen at midnight?
Look in your Console logs (system.log) for some answers about that.

 

[cupcakes2000]

Thanks.
All that's entered in the console consistently each night at midnight is:
Notification centre - turning off do not disturb, and re fetching information.
And bluetooth seems to restart itself as well.
Two drives are directly connected to usb 3. The others are by a new hub, also usb 3.

Nothing else happens at midnight, (not that I'll mention on here!)

Actually I have had a thought, with hindsight, I have always just presumed they unmounted, and remounted quickly. I have never witnessed that. Just presumed. They my never have unmounted in the first place, it might be a simple bug whereby the notifications pop up when the notification centre restarts. I will check tomorrow night and be watching.
I am fully aware I have probably answered my own question. Thank you for your help!!

 

[simonsi]

Notification centre - turning off do not disturb, and re fetching information.

Perhaps then it is issuing the notification from an earlier disconnect? Just a thought, try adjusting the time DND gets turned off and see if the messages still get issued at the new time...

 

[cupcakes2000]

Yeah I'm thinking along those lines as well. I'll try it all out when I have some free time at my studio.

 

[sixkiller]

I have the same problem, but not at a specific time. They just unmount randomly, then remount again. It worries me because I have all my files on it, so I purchased another external hdd 5TB to make a backup of my main ext hdd, and not keep it connected.

 

[flowrider]

^^^^See this thread. Common issue, not related to the OS IMO!

https://forums.macrumors.com/threads/disk-not-ejected-proper-since-1-update.1933727/#post-22469889

Lou

 

[jgelin]

My MyPassport has been doing this since 10.11.0 update. It doesn’t seem to have a time to it, but when the computer is asleep it is certainly more prevalent.
I was worried about the files I had on the drive too, so I got a MyBook 4TB drive which I migrated everything to, and it does not have the ejecting issues.
Really wish we could find a fix so I could assuredly use my original MyPassport.

 

[simonsi]

I have the same problem, but not at a specific time. They just unmount randomly, then remount again. It worries me because I have all my files on it, so I purchased another external hdd 5TB to make a backup of my main ext hdd, and not keep it connected.

TBH that sounds like a completely different problem...cable/driver/power/enclosure

 

[MikB]

Perhaps then it is issuing the notification from an earlier disconnect? Just a thought, try adjusting the time DND gets turned off and see if the messages still get issued at the new time...

Adding some observations to this a few OS versions later. in macOS 10.12.6 at midnight when "Do not disturb" (Notifications) kicks in I get a long list of messages about disks supposedly just were ejected wrongfully and quite a few other messages including Reminders. When checked just after this happens, no disks are actually disconnected, disk operations are never disturbed, the reminders are old and are in some cases already checked as done on my iPhone.

I have a similar issue on the iPhone (iOS 11) in that notifications arrives many hours later than expected. That would not seem to be related in any other way than that these concern Notifications.

When I disable/enable "do not disturb" I trigger this message flood again, with the disk wrongfully ejected warnings, so clearly this issue could be related to "do not disturb" getting enabled. When this happened just a few minutes ago, some notifications were about disks not connected, but that have been a few days before.

I changed the time of DND to see if the issue remains.