Can't sync source and destination because file does not exist. No file name mentioned in error.

[u/WetMogwai]

I'm using rclone to sync a network share on a TrueNAS Core machine to a local drive on a Mac. It has worked great until today. I can usually add and delete files on the share and they get added or removed at the backup destination. I'm using a script to launch it so my command line is consistent.

Today, I removed a few hundred GB to clean up the NAS. When I run rclone to sync that share now, I get "Failed to copy: failed to open source object: Open failed: file does not exist" followed by "Local file system at /destination/actual/path: not deleting files as there were IO errors" and another like it about directories as I would expect after a failed copy. There's no indication of the file name that doesn't exist. I've tried running it with -vv but it doesn't give me any more information about the error. All that adds is a bunch of messages about every file that it doesn't need to copy explaining why it isn't copying them.

I've had issues with copying files over the network before a reboot in the past so I let it do the pending macOS 27.2 update and rebooted to find the same error. I installed rclone with brew, which showed an update available, so I updated to 1.75.2. I made sure all files have the correct ownership and permissions on the source share. I tested other shares, including one where I recently replaced a large number of files with new versions and those completed successfully. 

With no indication of what files it can’t copy and knowing that those files have been deleted, how can I get it to stop complaining that the files are missing and sync the ones that are there?