duplicate folders / double directories

Too start with, Great product.


But I've have a little problem, I've now had this happen 2 or 3 times.

In the gallery dropdown list:
most (but not all) folders are listed twice.
Most (but not all) folders will list the same number of images.

Many of the duplicate folders will list (actual) number of images, but
many of the folders will list (1) image, regardless of the the actual number of images.
Many others duplicate pairs will list either (1) and/or (0)

Re-scanning galleries does not correct problem.
Renaming a folder and rescanning it corrects the problem (also corrects any subfolders).
But this has the side effect of clearing any aliases, custom descriptions and folder/ group connections.

Where is it storing and picking up the folder information from?
How can I force a rescan without renaming the folders?

Thank you