We're sorry about the trouble while trying to work with Lightroom 4.3. Would you mind telling us which operating system are you working on? Have you tried re-installing the app to check if that helps? If not, please try that & let us know if it helps. Also, try signing out of the Creative Cloud desktop app & then signing back in to check if that makes a difference.
If the issue persists, it would be helpful if you could share a screenshot of the application interface.