I notice that from time to time, I start DT (always the latest version) and all the databases are closed and are thus not showing. I then have to manually open the DBs I want again.
How does this unexpected closing of all databases happen and how to I prevent it. It’s always a shock when I search for something, but then see there are no databases visible.
Thanks in advance,
Databases are always closed on quit. But they won’t be automatically opened after launching if they were not properly closed, e.g. due to a crash or force quit.
I meant that the databases were “gone” from the display in Devonthink, not merely closed. I must have force-quit DT without realizing it I guess… ???
Thanks
Other possible reasons are e.g. system crashes/freezes, power outages or empty batteries.
Thanks, but none of those apply. 
Appreciate your kind replies, as always.
Do you see warning prompts when reopening the databases?
Also, you could look into workspaces…
It usually does a repair and finds something.
Perhaps that’s because it crashed or I force-quit it without realizing?
What kind of issue is usually reported? Missing or orphaned files?
I’ll let you know the next time it happens. Thank you!
Yes, that definitely shows you’re having an issue with the database(s).
Are you shutting the Mac down without explicitly quitting DEVONthink?
I never shut down the mac, but it does sleep and perhaps DT was left open.
This problem doesn’t happen very often which is why it’s so surprising when it does.
Fortunately, DT is very resilient and capable of fixing any problems with the databases.
I’ll keep a careful watch for a whilel
Thanks!
Perhaps off-topic, or perhaps not. macOS does better if re-booted every so often. “Never” is too long. 
Re-starting gives the machine the opportunity to clean things up and then start fresh. May have bearing on your occasional issue. Hard to tell, of course.
I re-boot my iMac about once a week or so.
Yes, in fact I had rebooted in the last few days. Generally once a week also for me after I run Onyx.
Thx
I quit DT when I’m not using it (I do that for all apps, not just DT) and have never had this issue except when I’ve forced a restart of my Mac, so I think as others have flagged something has gone awry with one of your databases and DT hasn’t closed down properly. I actually have the opposite issue - usually I only work from one or two databases, but sometimes I open others and forget to close them. Then I’m annoyed with myself when I open DT and do a search and it bring up lots of random stuff from a database I didn’t close before I shut the app last time 
You could use the smart rule script Close All Databases to close all of them on quit.
Thanks four your comments and insights.
Much appreciated!