A drive letter is a single alphabetic character A through Z that can be assigned to physical disk partition, floppy disk drive, removable device, CD-ROM, or even a mapping network drive in the computer. Generally, drive letter A: is allocated to the first floppy disk drive , B: to the second floppy disk drive, and C: to the first disk partition where the running Windows is installed. And the remaining drive letters can be assigned to other disk partitions, removable devices and mapping network drives in accordance with actual demands.
Once a letter is allocated to a disk partition or mapping network drive (letter for removable devices is changeable), we can say it is fixed unless we change or remove it in Disk Management, Diskpart, or some third party programs. However, one day we may find these fixed drive letters are missing in either Windows Explorer or Disk Management, which brings a lot of inconvenience and troubles, so in this post we are going to introduce some factors that can make our drive letters disappear, and then show corresponding solutions.
Drive Letter Missing from Windows Explorer or My Computer
Generally, after we open the Windows Explorer, we can see the following scenario:
Every local drive and every removable storage device has its own letter, like C: for the first drive, A: for floppy drive, and E for DVD drive. But one day we suddenly found all drive letters disappear, which is so strange though this brings nearly no influence on system running and data access:
What’s wrong? Where are these drive letters going? How can we get these lost drive letters back in several steps? Let’s deal with these questions one by one.
The most probable reason may be that you or someone hide drive letters via making settings in Windows Folder Options. To fix this issue, please take the following steps: go to one of partitions, click “Organize” tab, and choose “Folder and search options” from the drop-down menu to get the Folder Options (take Windows 7 for example):
Then, select the “View” tab and scroll down the sliding handle to the middle until the “Show drive letters” appears. With checking this option and click “OK”, we can see the missing drive letters in Windows Explorer again.
If you have known the reason for missing drive letter from Windows Explorer or My Computer as well as the solution, it’s time to know why drive letter disappeared from Disk Management.
Drive Letter Disappears in Disk Management
As we know, Disk Management is a Windows snap-in partitioning program designed to help Windows users manage disk and partitions. In Disk Management, every drive should have a drive letter, but sometimes we may find one or some of drives lose their letters like this:
Here we can see the 188.38GB NTFS partition does not have a drive letter. Generally, if a partition is not allocated with a letter in Disk Management, it will be invisible in Windows Explorer:
As a result, we are unable to directly access files saved in it, and all programs relying on the drive letter will be unavailable. Therefore, under this situation users would be more eager to get the missing drive letter back. Well then, why does the drive lose its letter and how to make the disappeared drive letter emerge again?
There are 3 possible reasons for this issue: users or viruses remove the drive letter; system does not allocate letters for some system-related partitions; the drive is hidden via special technology. Fortunately, by taking the following operations, you will find the missing drive letters or add new letters with ease.
Steps to Get Missing Drive Letter Back in Disk Management
In Windows Disk Management, the function “Change Drive Letter and Paths”, which appears in the right-click menu of a partition (Windows calls it volume), can help add, change, and remove drive letter:
If “Remove” is selected and applied, the letter of the target drive will be removed and disappear in Disk Management, which is one of reasons for losing drive letter. On the contrary, by clicking “Add”, we can assign a letter for the selected drive. Therefore, when certain drive loses its letter, we can try adding a drive letter in this way. But for successful adding, you may need to pay some attention to the following Tip:
We’d better assign the drive with the original letter. If not, programs relying on the original letter will be useless. For example, if we have created desktop shortcuts for some programs that are installed in the drive, all shortcuts will malfunction after we add a different letter for this drive, because system cannot find the correct path to launch the program via the “.exe” desktop shortcuts. However, if you have created new partition after the letter is missing, the original letter may be used by the new drive. At this time, there are 2 choices. One is to delete the original shortcuts and then create new shortcuts which are with recognizable path, and the other is to change the letter of the new drive to another available letter and then allocate the released letter for the target drive.
However, for some special volumes like system reserved partition, EFI system partition, recovery partition, and OEM partition, Windows does not allocate them with drive letters during installation, which is to prevent important files from being deleted and modified maliciously or mistakenly, but it does no harm to system and data. Therefore, under this situation, it is unnecessary to assign letters to these volumes and just keep the original state.
Apart from the above 2 factors, our drive letters will disappear after we hide the very partition via special technology. If a partition is hidden, the function “Change Drive Letter and Paths” will be unavailable (grayed out), so naturally we are unable to add it with a letter. At this time, the best solution is to unhide the partition by using third party program. If you have no idea of this kind of utilities, try using MiniTool Partition Wizard, which is free for Windows home users.
It is very easy to unhide a partition in MiniTool Partition Wizard, and detailed steps are as follows:
1.Run and launch the freeware to get its main interface:
2.Select the hidden partition and click “Unhide Partition” from the left action panel.
3.Select a letter for the partition and click “OK”.
4.Click “Apply” button on the top to apply the change if the missing drive appears in Partition Wizard.
When MiniTool Partition Wizard shows it succeeded in applying the operation, we can see the letter of the partition in Disk Management, and the missing drive will also appear in Windows Explorer. After getting a basic understanding of the second scenario, let’s see the third one.
Drive Letter Missing from the List of Available Drive Letters
We have said it is very easy to add or change drive letter for certain partition in Disk Management, but sometimes you may find such a strange situation where a specific letter is not shown in the list of available drive letters and no other device has that letter assigned. The most probable reason may be that this letter is reserved for a removable device that was removed or is hidden. Under this situation, if you want to assign the very letter for the specific drive, you may need to make some modifications in Registry. However, as a slight mistake in Registry may cause data loss or system crash, it is very necessary to backup the registry before doing any modification. For detailed steps, please see How to Backup and Restore the Registry in Windows. Then, launch Regedit, navigate to HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices, and see if a device is shown as being mounted at the specific drive letter. Next, right click the drive letter that you want and choose “Rename” from the right-click menu to change the letter to any other unused letter, which will free up the selected one.
After reboot, you can add the released letter for your drive. And next, let’s see the fourth reason for losing drive letters.
Drive Letter Disappears after Reboot
When browsing Windows Forum and Windows Seven Forums (2 well known technical forums about Windows) I found a lot of people were talking about the problem that drive letters disappear after every reboot. Of course, the same issue can be found in other websites or forums since this is a quite common error. Next, let’s see an example coming from Windows Seven Forums.
The following screenshot shows the 465GB NTFS partition on Disk 1 has the letter E:
However, after every reboot, the letter will be missing:
If the user wants o use the partition normally, he has to assign drive letter every time, which is so troublesome.
After lots of searches on Google I found this error often occurs on Western Digital hard disk, so it may be a bug of WD hard disk. And someone gives the suggestion: fill the disk with zero by using WD Data Lifeguard Diagnostic tool, and it has been proved to be a solution. For detailed steps, you can view the official website of WD. Actually, there is a freeware to do the same operation, and more surprisingly it requires much simpler operations. That is MiniTool Partition Wizard.
However, before zero filling the hard disk, users need to backup all desired files, because this will erase both file system and data. For steps to backup a disk, please see Copy Disk. After the backup has been created, we can wipe the disk without any worry.
How to Erase Disk with MiniTool Partition Wizard
Firstly, run and launch the freeware to get its main window below:
Here we can see all recognized hard disks. To wipe a disk, please select the target disk and click “Wipe Disk” feature from the left action pane to get the following interface:
There are 5 wiping methods in total, including Fill Sectors with Zero, Fill Sectors with One, Fill Sectors with Zero & One, DoD 5220.22-M (3 passes), and DoD 5220.28-STD (7 passes), and you can choose one of them to erase the hard disk. From the top to the bottom, erasing time increases but the effect is better and better. Then, click “OK” to go back to the main interface:
From the above interface we can see the entire hard disk 2 becomes unallocated, and there are 3 pending operations on the left side, containing delete partition I, delete partition H, and wipe disk 2. At this time, as long as we click “Apply” button, all changes will be made automatically. Once the disk is erased, we can recreate partitions in either Disk Management and Partition Wizard. And the new drive letters would stay in their original place next time you reboot the computer.
Now if you have known how to deal with the issue that drive letter is missing after Windows reboot, let’s see the last situation.
Drive Letter Missing in Map Network Drive
Drive mapping is how operating systems like Windows associate a local drive letter (A through Z) with a shared storage area to another computer over a network. However, these local drive letters may disappear in Windows Explorer without us knowing exact reasons. After a series of findings, we find 2 possibilities:
1.When mapping the drive, users do not check the option “Reconnect at logon”.
2. Use the Work online without synchronizing changes over a virtual private network (VPN) connection.
Now that reasons are found, solutions are available now. For the first situation, users just need to remap the network drive and check “Reconnect at logon”:
Is your drive letter missing or lost under Windows? Have your found the exact reason and corresponding solutions? If you have found, can you please share them with us if they are different from those introduced in this post? If you haven’t found goo solutions, this post may be useful.