Add my name to the list of users affected by this bug. I recently rebuilt my NAS and ever since the number of failures has shot up. To the point that I no longer trust Sonarr. My drives are shared over CIFS on ubuntu and are being written to from sab/sonarr running on Debian.
Helpfully, Sonarr marks the ‘failed’ transfers as purple because as far as it’s concerned it never receives a success flag from the OS that the transfer has completed successfully. It also doesn’t appear to receive a fail either so it never retries. In fact it can’t retry because the file has been unsuccessfully moved, not copied.
Would it be possible to change the move command to copy-verify-delete/retry? I appreciate that this will require more code but since this bug has been around for several years and no-one has ever identified a solution, there does not appear to be an alternative.
As it stands I’ve gone back to downloading missing files manually and bypassing Sonarr completely. Not ideal.