A big thanks to Graham Martin and everyone who spent hours posting this information. Using Windows 10 64-bit I had exactly the same problem as Mr. Martin, but this a new BIAB installation. Deleting the "MaxPluginsToScan.txt" file seems to have correct the problem for now.

Like Mr. Martin, I too purchased an unnecessary copy of Jbridge. It seems that we were both on the same path until discovering this help topic (first time to visit this site).

Thanks to everyone who contributed to resolve this situation.