Please follow the below steps
- Quit Lightroom.
- Navigate to the location of the catalog.
- Move the catalog to a different location(e.g. Desktop)
<Now Lightroom will not be able to find the catalog and will ask you to create a new catalog>
- Create a new catalog and import few images
- Quit Lightroom to check for the issue.
If working fine, Use Import from another catalog to import the images from the previous catalog.
Let me know if this helps.
It was a problem with the language chosen in the System Preferences in my Mac.
Apparently there was a conflict with Lightroom. I changed it, now everything works perfect again.
Until this is fixed in an update, use the Plug-in Manager under the File menu in Lightroom to disable the onOne Lightroom plug-in.
Hope it helps.