I'm using Cosmos 2006 Advanced Professional, SP 5. In general, I've noted that the software is in general unstable (subject to apparently random crashing - especially when viewing results, animated). However, the most frustrating behavior is that I will define multiple studies (with varying boundary conditions and material definitions of parts) and often older studies show errors or corrupted definitions for random reasons. Sometimes I'll go back into the Load/Restraint definitions that show errors and just have to toggle 'Edit Definition' to get the errors to clear - but sometimes I go into 'Edit Definition' and the surfaces or components I referenced are just gone. Has anyone else experienced this buggy behavior and can you suggest a fix?