I'm having problems with LightRoom 6.3 backups on a Windows 7 64 bit PC - this also happened on LR 6.2. On exiting LightRoom 6:
So, it appears to be the "Optimize catalog after back up" option that causes the failure.
Once in Lightroom, if I choose File ---> Optimize Catalog... it begins optimization then gives "Error: Your catalog was not optimized and Lightroom must restart. Lightroom will check the catalog for damage when it resumes". On clicking "Ok", it gives me the usual backup/Test Integrity/ Optimize catalog options you get when exiting Lightroom, which I hen choose to skip. On restarting it checks the catalog and starts up ok.
I assumed there was damage to the Catalog so I exported all the images (60,000) as a new catalog, without the negatives, created a new catalog and imported them from the "export" catalog. This has not resolved the problem.
Can anyone please help?