Why do you want to change drive letter?
The drive letter of system partition is normally assigned by Windows at installation.
And the drive letter is C. After installation, Windows still assign a drive letter
for any of your partitions on hard drive, flash drive, optical drive, USB drive,
card reader.
Sometimes, the drive letter will be unavailable owing to some operations and all
partitions are shown as Document, Game, Music. Thus, you need to give the partitions
a drive letter. Or you just want to change the original drive letter to another one.
Matters need attention to change drive letter
1. The hard drive contains your operating system and boot files will be set as
C: drive and all your software will be saved on it by default. Don't try to
change it, or you cannot boot your computer.
2. Sometimes, you may find that your computer skip one drive letter and assign
another available drive letter for your card reader. Maybe, your card reader with
one more slots, so it will have different drive letters.
3. A: drive letter or B: have historically been reserved for floppy drives.
4. If you change the drive letter of a partition or disk with software, it may
stop working. You cannot find the path of it. Fortunately, this is not a common
question with newer programs and apps. But if you have an old program or you
still use the old operating system Windows XP or Windows Vista, this may be a
potential problem.
5. The different removable drives will have a different hard drive letter.
How to assign a drive letter on Windows 10/8/7 with Disk Management?
When you encounter partition or disk problems, Windows built-in tool, such as disk
management, diskpart will your first choice. Below, I will show you how to assign a
drive letter on Windows 10/8/7 with Disk Management.
Step 1. Press “Win + R” to open the
“Run” window and type diskmgmt.msc in the box
Step 2. Right-click the drive you want to change, and selectChange Drive Letter and Paths in the pop-up window.

Step 3. Click Change to summon the next window.

Notice: If you want to remove the drive letter of your
partition, you can select "Remove" and follow the
instructions step by step.
Step 4. Select a drive letter from the drop-down list and clickOK. And you are only allowed to use a drive letter which is still
available.

Step 5. Confirm the pending operation and click Yes.

You can change drive letter in disk management. However, it may not work well at any
time. For example: when you connect a hard drive to another PC, the disk may not display its drive letter and you cannot add a drive letter to it
using Disk Management.
How to change drive letter on Windows 10/8/7 effortlessly?
Windows built-in tool can help you change drive letter in Windows. But, it's not
perfect.
Want to an easier way or more advanced features, you can use free AOMEI
Partition Assistant. It contains all the basic features, including Create Partition,
Delete Partition, Shrink Partition, etc. Besides, It will offer you more advanced
functions like Move Partition, Merge
Partition, Convert to Primary Partition, Windows to go creator, etc
Now, coming to our point: how to change drive letter
Step 1. Download AOMEI
Partition Assistant, install and launch it.
Step 2. Right-click the partition, then select Advancedand Change Drive Letter in the main page.

Step 3. Specify a new drive letter and
click OK

Step 4. Preview the final result and
click Apply to execute the further operation

Step 5. Confirm the following operations and click Proceed.

This article is also applied to change drive letter on Windows XP, external hard
drive, card reader, etc.
Summary
Windows built-in tool disk management can help you change drive letter in Windows
10/8/7. But it does not work well all the time. A third-party tool like AOMEI
Partition Assistant can be a better choice.
With AOMEI Partition Assistant, All the operation becomes very easy, even for a
beginner. Besides, it has more advanced features., including Move Partition, Resize
Parttion, Convert
GPT to MBR, etc. What's more, it can help you fix problems caused
by Disk Management or Diskpart, including The
volume size is too big, Mark partition as active greyed out, The extend volume is
disabled, etc.