~/sync/documents/DVEVONfiles/Testing/TestFolder/…
Which leads me to full disclosure. I use Resilio Sync to share the DEVONfiles folder between machines. (Hense “~./sync”) I turned it off for the earlier duplicate scenarios. And duplicates still occurred. So I turned it back on, and it was in place for the current incident. (I can turn it off again for testing this problem, but longer-term that’s tough because lots of other things depend on that sync.)
That’s causing the issue as DEVONthink is not aware that this folder is already synchronized by another app and therefore this causes race conditions and conflicts. And actually it’s not necessary for files indexed by & synchronized via DEVONthink.
Full disclosure is always appreciated. The devil is in the details., as they say. 
Ah, but please remember: I’d considered that and Resilio was disabled for the initial testing.(“PSUR…”)
Also, if Resilio was causing the problem I’d expect to see every new/modified file being duplicated.
That doesn’t mean Resilio wasn’t a factor in this most recent incident, but it’s clearly not the only thing going wrong.
Per Chris, I’ll pull my indexed folders out of the Resilio sync (there’s too much else going on to leave it disabled indefinately) Then I will clean up these duplicates and report if anything else happens.
Thanks!
Happy Sunday!
Quick question: I moved all of my DEVONthink folders out of the Resilio sync store. But DEVONthink’s complaining now that it can’t find them. What’s the best way for me to move the folders and maintain (or re-establish) the sync?
(Before this, I saw another dup this morning but I think my situation is f’d up enough that we can’t use it as a reference)
What do you mean “re-establish sync”? I thought you are not going to use Resilio sync?
If you are trying to get these newly located files into DEVONthink, then you can either Import or Index them. I suspect you want to Index them. So as to not repeat instructions, see the outstanding DEVONthink Manual , page 52 of the 3.8.6 PDF version.
What’s the best way for me to move the folders and maintain (or re-establish) the sync?
Following on @rmschne’s comment, sync is a very specific thing in DEVONthink. You don’t sync indexed files, you update them.
Regarding relocating indexed files, select the indexed parent group in DEVONthink, then click the flyout for the Path in the Generic Info inspector, and choose the new location.
Okay, here is my final report: I removed my indexed folders from the Resilio Sync setup and there have been no more duplicates generated.
It’s still puzzling, the duplicates generated were infrequent and randomly selected and I’d reasoned that if it was a double-sync issue it would reliably duplicate the most recently edited files. Not the case.
Probably some difficult-to-trigger race condition, but we’ll never know. Thanks for your help with this!
Thanks for the diligence and follow-up. We appreciate the effort 