I haven't had time to browse all of the previous strings...so if this is an old subject please excuse. Anyway... I just built an assembly (about 50 parts) and when I executed my last save on the last version of this assembly I got a message asking if I wanted to save the changes to the assembly and all of its depenants. I clicked yes. Now I'm unable to modify anything in the assembly, sub assemblies, or individual parts in their respective folders. What gives??? What locked these files so I can't edit them? Can anyone bail me out of this one??