Correct...that happened to me earlier this year.
Windows is waiting for you to reboot to complete a Windows update.
One big windows update required a couple reboots.
Reboot, wait 30 min, reboot again, wait 15 min, then try again with TTX.
(or repeat a couple more times with waits in between....if you have a slow internet connection, some updates take a whole day or overnight)
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
