When you import a file into Devonthink, or when you save a file into the Devonthink inbox, DT finds a place to put it. The DT database is a MacOS package, which means it a folder like any other folder on your system except that the Finder will display it as one monolithic thing.
Devonthink manages a tree of folders inside the database package that bear no resemblance to the groups you see in the Devonthink application.
The most important thing is that Devonthink decides where an imported file goes. It keeps track of where it put your file and it also keeps track of where you want to see it in the groups you create in the user interface.
When you rename a file outside of Devonthink, you’re renaming a file in a Devonthink-managed folder. To Devonthink, a file that’s supposed to be there can’t be found. There’s a new file that would get picked up if you repaired the database, but Devonthink would never know that file was really the old one.
For instance, I created a Markdown file called testjunk containing “Hello, world.”
I right clicked it, used the “Show in Finder” option we probably should never use, and renamed it from testjunk.md to not-here.md outside of Devonthink.
The log window popped up with an error and I got the missing file display for my now “missing” testjunk file.
Once again, I used Show in Finder on the missing file, this time just getting to the internal folder where the file was stored. Sure enough, in that folder was not-here.md. I renamed it back to testjunk.md and Devonthink was happy again.
Of course, never do that. If I had any self esteem, I wouldn’t, either.
Let Devonthink handle file names and internal locations. And never use an application’s lock feature. Lock files in Devonthink. The padlock in Pages will interfere with DT’s file management. I will never admit why I know that other than to say @BLUEFROG is an excellent resource.