Hi

Assuming you are using Photo Manager 15 - I can find no Multiple rename option in the program even though it is mentioned in the manual.

I use a seperate program - Advanced Renamer -  for bulk renaming of files.  It takes a little getting used to however the help is very good at getting you started.

Using this will however mean you have to update the Photomanager database after using it.

HTH

John EB