All, thanks very much. I was not keen on doing a re-install (& not sure what a repair option is).

Finally took the plunge, and started Liquid 7.2 update (without any un-install). Watching all the install messages I fleetingly saw .....Rapid(Liquid)..... install message.

Have now retried - and error message stopped - great.

Next I must try to reduce my dropped frames (my disks are not indexed, and network/firewall/anti-virus disabled during editing).