Some are reporting license issues with the latest release of Revit. The following text is from the Autodesk knowledge base files.
When you reinstalled Revit®, the serial number was changed to 000-00000000.
This problem affects authorization, built-in subscription features, and Autodesk error reporting.
To fix the problem
Locate the Revit.exe file. Depending on your installation, this file can usually be found in one of the following directories:
C:\Program Files\Autodesk Revit Building 9\Program
C:\Program Files\Autodesk Revit Structure 3\Program.
In Notepad, open the licpath.lic file.
In the licpath.lic file, locate the serial number (#SN 000-00000000) and replace it with the correct serial number.
Save the licpath.lic file.