I'm working on a project that consists of many subassemblies.  As I complete each subassembly, it is fully mated and resolved without errors.  I also have the subassembly mated and without errors in the higher-level assembly.  When I close SW and reopen it, usually the next day, everything blows up because all of the mates are suppressed.  I haven't changed configurations, so I know that's not the problem.

What's going on?  Have you guys seen this before?