I use an external disk to backup several photo and video structures. I have forced the external drive to always use the drive letter V: so that the Left Folder is C: and the Right Folder is V: with the exact same path used on both disks. I will use it once
or twice and then go a while before using it again. Then I get into SyncToy 2.1 and the Right Folder has C: and effectively compares the files with themselves. The only option I have found is to delete the folder pair and re-establish it then the cycle starts
over again with it working for a while.
I have not found any way to force the folder pairs to re-extablish them selves.
I am running Win 7 Pro 64 on a Dell Inspron 1440; SyncToy 2.1 ver 2.1.0.0 built 10/19/2009 3:04:38