session missing waves plugins

Audition 2021, PC, Waves 13

So yesterday (Fri 12.3) I started work on a program using a session file pre-loaded with all my effects.  I use this session file on a weekly basis.  Everything was fine; all Waves plugins were present, accounted for and working.  As I was waiting for a producer to get me a couple of audio files I needed to complete the program, I saved the session and closed Audition.

Today (Sat 12.4) I received the files I needed, so I reopened the session.  I'm presented with the following message: "Warning: 5 of the 8 effects referenced by the file could not be found: CLA-2A Stereo, REQ 4 Stereo, NS1 Stereo, Dorrough Stereo, WLM Meter Stereo."

Nothing I've tried will allow the session to recognize the Waves plugins.  I've done oodles of plugin rescans, among other things.  I'm looking for a solution to this dilemma.  

Thanks.