Error message (OSStatus error 640)

Hi,

After i've searched for duplicate items on my external hard drive, and click to delete them and replace them with aliases with the app "Tidy Up", I get this error after some time:

Execution stopped after getting error:

The operation couldn't be completed.

(OSStatus error 640.)

When I search this error appears to mean "invalid BackingFileID", but another site says it means "NSFileWriteOutOfSpaceError", but I don't know what this means or what I can do to fix this error.

Does anybody have any suggestions for me?

Thanks. 🙂