The blog of Windows Wally, a Windows Support Technician helping common people solve frustrating computer problems.


Reader Question:
“Hi Wally, I turned my computer on this morning and Windows won’t run anymore. Its saying ” Assign drive letters failed “. I don’t know how to fix it. Can you help me?“ - Stephanie Y., United Kingdom

Before addressing any computer issue, I always recommend scanning and repairing any underlying problems affecting your PC health and performance:

  • Step 1 : Download PC Repair & Optimizer Tool (WinThruster for Win 10, 8, 7, Vista, XP and 2000 – Microsoft Gold Certified).
  • Step 2 : Click “Start Scan” to find Windows registry issues that could be causing PC problems.
  • Step 3 : Click “Repair All” to fix all issues.

Setting up weekly (or daily) automatic scans will help prevent system problems and keep your PC running fast and trouble-free.

Wally’s Answer: This error usually occurs right when a user turns their computer on and Windows starts to load. Windows assigns drive letters to partitions in order to identify them. If something does not allow this process to complete, then errors like this appear.


The computer does not load Windows, showing an error saying Assign drive letters failed. It has the error code: STOP 0×00000072.


A faulty device driver usually causes this error to occur. The device may have been installed recently.


Here are some ways to fix this error:

Did You Install Any New Hardware Recently?

Chances are that you had connected some new hardware to your computer. The driver may have malfunctioned and caused this problem. You may be able to fix the “ Assign drive letters failed ” error by disconnecting that hardware device from your computer and then restarting the computer.

Make sure that your new hardware is compatible with the version of Windows you are using. If Windows still shows the same error then follow the next step.

Use The Last Known Good Configuration To Fix The “ Assign drive letters failed ” Error

This will only work for Windows 7 and lower versions of Microsoft Windows. Restart the computer and keep pressing F8 to see the Advanced Boot Menu. Choose Last Known Good Configuration.

Safe Mode with Networking

If using the last good configuration didn’t work, then Restart the computer, keep pressing F8, and this time choose Safe Mode with Networking instead. Wait for Windows to start and try to delete any recent device drivers you may have installed. Also, try to install the latest Windows updates.

Since ” Assign drive letters failed ” is usually caused by faulty drivers, install official device drivers from the manufacturer’s own website. You can use a driver utility called DriverDoc to update all device drivers from official sources automatically.

Using System Restore To Fix Things Quickly

You can also restore the system restore point from Safe Mode. Press the Windows Key > type system restore > click System Restore, and follow the instructions to restore a system restore point if one is available. Click here to see how to use System Restore in more detail.

You can also access system restore by using a bootable Windows setup disk. Restore the system restore point from there in case Windows is not even starting in Safe Mode.

I Hope You Liked This Blog Article! If You Need Additional Support on This Issue Then Please Don’t Hesitate To Contact Me On Facebook.

Is Your PC Healthy?

I always recommend to my readers to regularly use a trusted registry cleaner and optimizer such as WinThruster or CCleaner. Many problems that you encounter can be attributed to a corrupt and bloated registry.

Happy Computing! :)

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About the Author

Windows Wally is a helpful guy. It’s just in his nature. It’s why he started a blog in the first place. He heard over and over how hard it was to find simple, plain-English solutions to Windows troubleshooting problems on the Internet. Enter: Windows Wally. Ask away, and he will answer.