You will know a disk has an active partition by going into the Disk Management Console. So let’s just mark it as an inactive partition and get it over with.

This causes it to go through the whole auto run thing every time you plug it in and if you boot while the drive is connected it gives you a fit because it wants to install the OS or can’t find bootable files.

The problem with that is you can’t just go back into the disk management console and right click and unmark a partition as active. I will usually extract all the Windows install files onto the root directory of my external hard drive, make it bootable (Mark the partition as active) and install from there. This is a problem though when reinstalling the OS. The vast majority of the time I don’t mind as I pretty much use ISO files exclusively. I have a laptop without an optical drive in it. That or your even more like me and you download some beta version of software and install it on your laptop rather than a VM and screw something up to an unrepairable state. If you are like me then you like to reinstall Windows on your laptop every few months to keep things fresh and running smoothly.

Mark disk