Selecting a scanned folder fails due to the folder belonging to a non-existant library

A folder that is part of an Aspect library cannot belong to a different library at the same time. If the folder you select as the scanned folder already belongs to a different library, but that library doesn't exist in its expected location, you need to decide how to continue.

If the library still exists somewhere else, simply load it by using the “Browse…” entry within the “Library” menu to access the photos in that folder.

In case the library actually does not exist anymore, you will have to remove the catalog file that associates the folder with that library. Depending on the type of folder, there should be an Aspect Event File.aspectnode or an Aspect Individual Photos File.aspectnode file, either in the folder itself, or in one of its ancestor folders.

After this file has been deleted, you can choose the same folder again and it should be selected successfully as a scanned folder for the new library.