Page 871 - Windows 10 May 2019 Update The Missing Manual: The Book That Should Have Been in the Box

Windows generally assigns these letters in the order you install new drives

to your system. You’re not allowed to change the drive letter of any startup
hard drive (the C: drive and, if you’re set up for dual booting, any other
boot drives).

You can, however, override the other drives’ unimaginative Windows letter

assignments easily enough, as shown in Figure 17-3. Your computer won’t
run any faster, but you may feel a tiny surge of pride at how much better
organized you feel.

Note
If Windows is currently using files on the disk whose drive letter you’re trying to change, Disk
Management might create the new drive letter assignment but leave the old one intact until the
next time you restart the computer. This is an effort to not pull the rug out from under any open
files.