Jim,
Thanks for your reply. I've tried several different things so far, none have been successful.
So far I've downloaded MC 15.0.173 and performed a successful download of the ".mjr" reactivation file. I then tried the following:
1. Uninstall, restart, reinstall, then run activation file.
2. Library backup, complete uninstall, then run activation file.
3. I have a pretty bare-bones Win7 Ultimate installation, so I went for the nuclear option and reinstalled Windows.
However, I'm still having trouble. Running the ".mjr" license file results in the message "Error restoring Media Center license: Unknown Error" each time.
Norton and Windows Defender are off. I also tried to install version 15.0.169 to see if this was related to the minor license change listed in the 15.0.171 log. Anyway, no luck so far and I am back to running a 30-day trial version.
Anything else I could try? Is it possible that my registration mjr files are corrupted somehow (the email lists 6 reactivations left)? I'd be happy to provide additional information if that is helpful.