Hi Andrew,
Thanks for the rapid response.
Unfortunately, your suggestion of reinstalling some of the RT sets ( containing the missing/damaged RDs) had not remedied the problem.
Motown funky triplets, New Orleans shuffle, Boom Chicka are not being generated.
Whenever I open the RD picker there are 697 items ( 727 after rebuilding ) with the Rds in question among them (not missing). When I add the N/A there are 742 items. All the 15 N/A generate drums, even that the Mixer tells me they are missing, contrary to these 3 RDs ( not missed in Mixer) which are not being generated.
It would be spooky/funny if it were not annoying.
I hope it makes sense for you ( I'm completely clueless )