How do I troubleshoot Windows 10 system disk drive letter loss?

On the window 10 desktop, we find "this computer" and then we right-click it, click "Manage" in the pop-up menu and then in the Open storage menu of Disk Management, at this time you see the disk partition situation on your computer. One of the drivers is missing, and the original D disk disappears, as shown in figure:

Now we find and click Two partitions, then right, then we choose to change the drive letter and path to click Add, select the following drive letter to add the letter as shown below.

Of course, if our letter is wrong or if we want to change the letter, I just need to change the drive letter and the path window to select Change.

The disk drive letter problem is solved, in fact, is not lost but we do not understand the system, so your friends still know more about the Windows 10 system.