Do you get any error message? or does anything happen at all when you attempt to start Photoshop?.
If you are using Windows go to this location
C:\Users\%USERNAME%\AppData\Roaming\Adobe\Creative Cloud Libraries\LIBS
This path is hidden by default. You must use Folder Options to make it visible
Type folder option into the search box and click on the option to open it
Adjust the settings so they match the highlighted areas here and press apply
%USERNAME% will generally be the account name you used to sign into Windows. So if you use the Administrator account this will be
C:\Users\Administrator\AppData\Roaming\Adobe\Creative Cloud Libraries\LIBS
You might see a file called librarylookupfile, if its there rename it librarylookupfileOLD and restart Photoshop.
Finally go back to Folder Options and hide the Operating System files again
Give it a go and let me know if it works
Terri