This error will usually occur when launching Unity Pro. The working drive specified in the registry may be incorrect.
Open the Registry Editor and go to the following path:
Make sure the working drive is a valid drive, usually C:\.
Legacy KB System (APS) Data: RESL212560 V1.0, Originally authored by DaSo on 09/21/2013, Last Edited by DaSo on 09/21/2013
Related ranges: Unity Pro - SoCollaborative software