What does it mean when Retrospect Express displays Error 205?
This usually indicates the bus was reset during a backup function (Duplicate in this case), causing Retrospect to lose contact with the hard drive. This error usually indicates a device communication problem and may be accompanied by an error 102 (trouble communicating).
If error 102 does not accompany error 205 and device communication problems have been ruled out, the next step is to check for media failure on the source volume. Some hard drives reset the bus when they sense they are experiencing a media failure. Try testing the hard drive with the software that was originally used to format it. Try running some disk scanning utilities on the source volume.
You could also get an error 205 and it means that the volume is not accessible at the time of Retrospect trying to access it. Make sure the source hard drive was not unplugged during the Duplicate operation.