I have a user that is getting an error when he opens 2013 that says "Failed to initialize the add-in "Worksharing Monitor" because the assembly "[TARGETDIR]WorkSharingCommand.dll" does not exist". So I figured I'd open the addin file and make sure it was pointed to the right path.
The Workshare Monitor files are installed properly to Program Files(x86), but i cannot find the addin file. I can find the addin file for 2011 and 2012, but nowhere can I find it for 2013. I searched on my PC as well, and no luck.
Windows XP: C:\Documents and Settings\All Users\Application Data\Autodesk\Revit\Addins\2013\
Windows 7: C:\ProgramData\Autodesk\Revit\Addins\2013\
If it's not there, I would try repairing the installation of the Worksharing Monitor through the Control Panel. If the issue continues, I would copy a working version of the add-in file from a working machine to the one that is not.
Chris Aquino Technical Support Specialist Customer Service & Support Autodesk, Inc.