I had installed V19 over V18 which i guess is a good? or bad? way of doing it.
So paths should be transfered.
I do however have Onedrive but this does not seem to be a probelm with V18.
I would like to say that having to uninstall V18 to install V19 a bit archaic as other programs on a PC manage to overinstall OK. Also I have no other program that has so much trouble with Onedrive folder/files.
This might be related to an issue discovered post-release with some library index files. We have a hot-fix available (please contact support@numberone.com to request it) and will be issuing 19.0.1 very soon as this problem appears to be affecting more people than originally suspected.