The (Global) Inbox stop again syncing between my two macs. 
I’m sure I will be able to sort it out by creating another new sync store, but of course that’s not ideal.
My newest suspicion: Maybe High Sierra is to old? One of my Macs is on High Sierra, the other on Mojave. - Can that be the problem?
There is no known sync issue related to the OS. However, we suggest moving to a more modern operating system when possible.
Did you check whether any errors were logged first (see Windows > Log)?
No Inbox-related problems in the Log window.
(On databases with files in indexed folders I have sometimes mysterious “Missing File” errors in the log, but I don’t do indexing in my Inbox, so I don’t have trouble with these for the Inbox.)
This can e.g. happen if indexed items were deleted/moved/renamed by the Finder or other apps and DEVONthink’s database isn’t up to date yet.
It happens for me on files which are present in the Finder.
Only way to solve this is: (1) Trashing the indexed folder, (2) emptying the trash (without deleting files and fodler on the filesystem1), then (3) re-adding the stuff as indexed folder.
Still with the same name and path? A screenshot of the Info inspector for such an item plus a screenshot of the enclosing folder in the Finder would be useful next time.
I’m sure it’ll happen again. I’ll screnshot it then.
Somehow the Inbox doesn’t want to sync between the two Macs even with a totally new sync store!
What details would you need to trouble shoot this?
E.g. messages in Window > Log
Sorry, wasn’t patient enough: I had to wait for hours, but now the Inbox is synced again. Yeah!
What kind of sync location do you use?
I sync via Dropbox.
Do you have made better experience with other synced filesystem providers?
FYI, Dropbox works fine here and has for years.
I think the sync problems happen only on the High Sierra machine - because the Mojave mac syncs its changes properly to my iOS devices. That’s where my suspicion with Hig Sierra came from…
@cgrunenberg Are there other logs which I could check? As said the Log WIndow stays empty.
I’m confused as you said this earlier…
Fair enough. To explain it better (or maybe I should have opened a new thread):
Now another database named General is not syncing correctly - again only on the High Sierra mac.
But nothing’s logged to Windows > Log?
No, in regards to the database General nothing is logged.
(In regards to another database something like:
11:43:05am | ~/Dropbox/docs/folder/path/document.pdf | skipped
is logged on both computers.)
Did you try to manually synchronize the databases? And did you check that the databases are all enabled for this sync location on all devices (see e.g. Preferences > Sync on the Mac after selecting the sync location)?