WL Elements 9.5.35 - Editing Mono files - macOS 10.12.6 - SOLVED

Is there an issue about editing Mono files using WL Elements 9.5.35 under macOS 10.12.6?
If I duplicate copy one side of a stereo file it plays back just a tiny loop of the mono file, although cursor is moving normally.
If I preview a mono file from the file browser it plays back fine.
If I open this file it plays back just a tiny loop of it although cursor moves normally.
(Using RME Babyface Pro v3.10 or internal Mac sound)
EDIT - SOLVED - I did a complete clean reinstall and everything is now correct! I had the trial of Wavelab Pro 9.5 installed so maybe that was a problem? Anyway all good now.