Yeah, I'm glad the auto cleanup solved it.
If it helps for anyone in the future, here's what seems to have led to this. I was making copies of copies of copies of block diagrams and creating new VI's based off of the same essential layout. This would have been a good opportunity to wrap them into a common subVI, but for other reasons this was not really an option. After creating about the 10th copy, this saving issue popped up. I had basically one top level VI that would call these copies based on a case structure input. Again, there were no linked tunnels. The only thing that might 'link' them together is a common Enum TypeDef that they all shared. In each VI copy, a different value was chosen for the enum. And they had other slight differences internally after the copies were generated.
Some of these VI's were generated using a "save as" function, while others I was copying the block diagrams from one vi to the other. All of this occurred in a project that remained open for the whole process, so perhaps the environment got overloaded in some manner. Anyhow, I don't know if these 'details' help, but I figured I would throw it out into the LabVIEW forum ether.
