Unable to Change Letter/Assign Drive Letter to D

Change A Drive Letter in Disk Management

It's supposed to be easy to change a drive letter to a needed one or assign a new drive letter, except the default C: for system partition/boot partition. Theoretically, any letter among D, E, F, G, H... can be chosen and used for other primary partitions or logical partitions. Here's how you change, add or assign a letter of the alphabet to the desired drive in Windows Disk Management. Note that you must be logged on as an administrator to perform the following steps.

Step 1: Open "Disk Management" under Storage by right-clicking "Computer/This PC" > "Manage".

Step 2: Right-click the drive that you want to change, and then click "Change Drive Letter and Paths".

Do one of the following:

To assign a drive letter if one has not already been assigned, click Add, click the letter that you want to use, and then click OK.

To change a drive letter, click Change, click Assign the following drive letter, click the letter that you want to use, and then click OK.

To remove a drive letter, click Remove, and then click Yes to confirm that you want to remove it.

Why Can't Change or Add a Letter As Wanted

How to fix the issue of not being able to make a change to the existing hard drive letter? For example, change D to E, or assign a new drive letter as wanted to a newly created hard drive. See what is causing the problem and how to get rid of it.

• The drive you're trying to change might be in use, so you are disallowed to make any changes to it. Just close the program or Window that is using the drive and try again.
• The drive you're working on is either a system partition or a boot partition. You can't make changes on it.
• When you change a letter or assign a new letter to a certain drive but suddenly found that the letter you wanted is unavailable in the drive letter drop-down list, however, the letter is not taken by another drive. Then it might tell you that the letter has already been used by some external storage media that is being connected to the computer right now. Usually, the rule of Windows drive letter assignment is like this.

Windows uses MountMgr to manage drive letters. MountMgr will assign the next available drive letter to each device added, regardless of type. With the system drive assigned the letter C, there may be other IDE, SATA or USB devices, such as a DVD ROM or a Flash drive assigned to letters D and E. When adding another drive, Windows will assign the next drive letter available, which in this case would be the drive letter H:

So if there are some external storage devices inserted into the computer, unplug it, and try it again.

If all the listed circumstances go against your case, e.g., the H letter is not being used by another internal or external drive, but it's still unavailable, then try to fix in this way.

EaseUS Partition Master Helps Change Drive Letter & Label in Windows

 

Step 1: Run EaseUS Partition Master, right-click the partition, and choose "Change Drive Letter".

Step 2: In the new window, click the down arrow and choose a drive letter for the partition from the drop-down menu, then click "OK".

Step 3: Click the "Execute Operation" button in the top-left corner, check the changes, and click "Apply" to change the drive letter of the selected partition.

It's better to have a try than not. There might be some errors in the hard drive which disallow you to make any change on it. EaseUS free partition manager works almost the same with Windows Disk Management in managing hard drive, including change drive letter and paths, but it does even more.

Check partition for errors:

Run EaseUS Partition Master, with which you're able to check file system errors, call Windows chkdsk.exe, Windows Scandisk application to fix errors, have a surface test. 

Change drive letter and drive label:

Right-click the drive, choose either between "Change a drive letter" and "Change label", then you'll be navigated to the drop-down list of available letters you can select to use. Apply the change in the final. Done.

There are massive features waiting for you to explore. EaseUS Partition Master shall become your ideal choice to organize your computer hard drive's letters and other info. Give it a shot.