Problem with assembly losing sub-assembly

Hello,

I have an assembly that i was working on, completed in fact. And when i opened it up one of the subassemblies completely disappeared

When i open up the sub assembly i have no origin, planes, mates, parts or anything

The reference to the part is still intact, i even opened up the part and renamed it and re-referenced it, no help

I have shut down computer and restarted sw

Attached are three screen shots of the affected assembly

I am running 2012, has not had this issue before

SolidworksAssemblies