You can see the full path of deleted empty folders as follows:
1. Bring up the Backup Tool.
2. Select the backup line of the run that you know included the deletion of empty folders. You have to know since there is no indication in the list.
3. Right click the line and choose the "Explore" action.
4. Open the dirs.dat file with notepad.
Example:
Dirs=1
1=C:\Users\Public\Documents\sun\