I recently tried using a OneDrive shared folder as the storage destination, and ran into an error saying some operation could not be performed on a mounted folder (first described here: Moving OneDrive token files)
After further testing with the CLI with debug enabled, I found that CreateDirectory is the operation that is being rejected.
After quite a bit of trial and error (I’ve never used either the OneDrive API or the Go language, so this has been fun!) I now have “init” working with a shared folder. The changes to add this support can be viewed here: Trying to support shared storage · rickparrish/duplicacy@8fb4a20 · GitHub
“init” doesn’t appear to call ListEntries, DeleteFile, and MoveFile, so those changes have not been tested yet.
I was going to try backing up a test directory, but then I noticed there appears to be a test function for OneDrive that calls these methods, and thought that might be even better. Unfortunately I’m not sure how to invoke that test method! Is there a secret command-line parameter? Or some other way to call it?