Another installation is in progress

#1
Trying to install using the 18.00.18 version (posted 18 minutes ago :-)

I get the "Another installation is in progress. You must complete that installation before continuing this one". I terminated the install, restarted, get the same error.

There are no Take Command or TCC processes running (at least none that appear in Process Explorer, anyway). Win7, 64 bit.
 
#3
None that I'm aware of. I was trying to upgrade from v13 to v18. I had a 18.00.16 build from the weekend. When that failed, I went to the forums, and saw that you had *just* posted a new 18.00.18, which I downloaded. I tried it, and got the error.

I was looking for TCC/Take Command processes, and there were none. What process names should I be looking for?