Same here... how did you sort it?
I deleted the LR using Windows Control Panel/Programs and Features/Unistall. I then re-installed from the CC. At that point I had to open the last backup catalog I had. The lesson is to always do a backup before getting crazy with the delete options!
Yup, last time for me. Needed to free some HD space halfway through editing a paid shoot, as I was running low.
Ended up getting my serial number through logging in to Adobe, but wasted precious time.
This update has given me nothing but a grief, will wait till the bugs are ironed out next time.