Can I Turn Off External Drive During Scan After Restart

During the first restart after downloading and initiating the install of the Win 10 Ann Update (1607) via Windows Update, I am getting the message "Scanning and Repairing drive (F:): x% complete. This scan is very slow. I neglected to turn off or disconnect an external hard drive before initiating the restart. Since this scan of a 500GB drive is probably going to take several hours, if I just disconnect or turn off the external drive, will it just abort the scan and proceed with the restart, or will that mess everything up?

Well I took a chance. I turned off the external hard drive and forced a shut down of the computer. I restarted the computer and got a "Attempting to restart ... installation" message. It quickly restarted again, and after about 20 sec. resumed the installation.

Lesson learned: Turn off external hard drives before installing a major update. I have since found several websites that recommend this, but the update itself does not warn to do so and probably should, since you don't have to do with other Windows Updates.