There are times when you might notice that the Drive letter from the File Explorer is missing, right after you install an update in your Windows 10 computer. So if you are facing this issue right now, then you’ve come to the right place as this post will guide you on what to do to fix it.
In case you don’t know, a drive letter represents a single alphabetic character which is through A-Z typically. This could be assigned to a physical disk partition, floppy disk drive or the removal device/ CD-ROM/ mapping network drive in your PC.
In most cases, the drive letter “C:” is assigned to the first disk partition where the running Windows is installed. Thus, if the assigned letter is missing from either the Disk Management or the Windows File Explorer, it could result in inconveniences or will leave the partition inaccessible. To fix this problem, you can try to show the missing drive letters manually or make sure that the drive has a drive letter assigned in the Disk Management as well as assign the letter using a tweak in the Windows Registry. For more details, refer to the options provided below.
As you know, every drive is assigned a drive letter in Disk Management. However, if it goes missing, you can still get it back through Disk Management. To do so, follow the steps below.
Note: This function allows you to add the drive letter, remove the drive letter and change the drive letter. If the last option, namely, “Remove”, is selected and applied, the letter of the drive will be removed and won’t appear in Disk Management. Thus, this could be one of the reasons why a drive letter is missing.
The next thing you can do to fix the problem is to assign the letter using a tweak in the Windows Registry but before you do that, make sure that you create a System Restore point first, after that, follow these steps:
Formatting the drive can also help you resolve the error. To format it, follow these steps:

Error Causes
Bug and security fixes:
Error Causes
Error Causes for 0x80070002Error code 0x000000D1 is a serious error that is displayed when Windows automatically shuts down to protect the system against further damage.
Usually, when this error occurs, the message displayed to the users states something like STOP 0x000000D1 DRIVER_IRQL_NOT_LESS_OR_EQUAL.
What Causes 0x000000D1 Error?Usually, the STOP 0x000000D1 error code is caused by issues like incompatibilities, third-party drivers, driver conflicts, outdated drivers, malicious drivers, and other related problems.
Speaking technically, the message displayed to the user actually means that the kernel-mode driver has tried to gain access to memory at an unreasonably high process IRQL.
If left unfixed, STOP 0x000000D1 error can become quite serious. Increased frequency of occurrence may not only lead to data loss but can cause system corruption as well. That’s why it is crucial to fix it and to resolve the underlying issues causing it as soon as possible.