(My apologies if this has been logged before.)
I used FireFox Portable (FFP) as my test directory pointing the destination to my existing FFP backup directory.
When performing the first mirror, Toucan proceeded to delete all the files on the destination that (presumably) did not match the source, but then did not copy these "missing" sources files to the target, leaving the target in a broken state.
I'm not sure why it deleted the files in the first place as it was supposed to be a backup of the source to start with. Possibly the "2-second" timestamp issue when copying between XP and Linux?
Only after a subsequent mirror was the integrity of the mirror restored by copying the "missing" files (that it deleted in the first place) to the target/destination.
I'm not sure if this behaviour is due to a bug/logic error, but I would suggest copying the files first so as to ensure the destination is always in a secure state. Overwrite anything that does not match the source, regardless if it is older/newer.
Thanks for a good tool and all the good work you are doing on the PA forum.