Mind if I email them to you or put it into a ticket?
...it happens pretty consistently.
Perhaps try this:
- Connect to a site
- Load a template into visual studio
- Edit it...
- Leave your pc for 10-15, come back
- Try to save again?
...I don't know what would reproduce it to be honest, if step 4 is even why it's happening. But I do know that when it happens I have to log into the site and kick the thunder user out...and the **ONLY** thing I'm doing is editing templates...and thunder always shows that it's still connected.