"An error was encountered while trying to open your file"

A few times a day we get the following error:

An error was encountered while trying to open your file.

Contact Technical Support for a possible solution

It occurs when opening files or even when saving files. Filetype doesn't matter. It also doesn't matter if we save files locally or on a network. This is a very unclear message and I don't know what to do with it. It occurs on different Dell T3500 workstations with Win6 x64 / Solidworks 2011 SP1 x64.

Has anyone encountered this message before? I can't find it on any forum...

Thanks

Pim

SolidworksGeneral