It seems you are trying to open a catalog created or upgraded in newer version of Lightroom in an older version.
Please upgrade your Lightroom version in order to use that catalog.
To check the version of Lightroom :
Click on Help > About Lightroom (In Windows)
Click on Lightroom > About Lightroom (In Mac)
Hope this helps.
Is upgrading through the creative cloud app not upgrading? Because I tried that and it still wont work.
Sent from m
How exactly are you opening that catalogue? Precisely what steps are you taking?
Are you certain you are opening the latest version of Lr?
If you upgraded from LR5 to LR6/cc, the two programs are installed side-by-side, both on the hard drive. Sometimes the desktop icons do not get updated during the install. Check to make sure you are running the correct version.