@ChristineJoieR thanks for your reply.  THis is a new problem, as I said, I have been running this report for 3 years but this week is the first time the list of Vendors has disappeared in the customization option and it's replaced by the "Non Specified" screen shot I posted.

I guess this is an issue I have to talk to support about.  Maybe it's only happening to my account?  I have over 100 Vendors stored and I usually easily run the report for a specific vendor, but that option is not longer showing on the Customization screen.