I’ve discovered a nasty problem with Revit 2010 when licensed with a network license. Autodesk’s FLEXLM solution allows for a TIMEOUT variable which we had to establish for previous versions. This option would return a license if a product crashes without successfully relinquishing the user’s license. This avoided falsely exceeding the actual number of licenses reported in use. In Revit 2010, the TIMEOUT seems to be enacted when your program session becomes idle beyond the duration of the TIMEOUT. On several occasions, I have left my desk to discuss a project with a colleague only to return and find I cannot save because I lost the network license connection.
This issue has been reported to Autodesk Support and I am awaiting a solution. Until then, if this is happening to you…be sure to save (locally and/or centrally…sorry, synchronize with central) frequently and especially if you are leaving your desk, checking email or anything other than actively working in Revit.