Microsoft has acknowledged and fixed a bug in Windows 10 that could have caused critical issues on systems running the chkdisk tool. This is a tool that can be crucial in case of issues on the computer’s storage system: it can be run via command line and allows you to check the volumes of a storage device and look for logical or physical errors on file system metadata. By running it on Windows 10 2004 and 20H2, users could have damaged the file system and prevented future access attempts.
The problem, and how to fix it
Microsoft has not yet specified on which Windows versions the problems could occur as a result of running chkdsk, an issue currently reported only on the pages dedicated to updates KB4592438 and KB4586853 released for Windows 10 2004 and 20H2, in December and November respectively. The bug was reported by Günter Born, after Planet3DNow users had already reported it publicly.
Microsoft explains it like this: “It has been reported that on a small number of devices on which this update has been installed, the file system may become corrupted after executing the chkdsk /f command, and the device will no longer boot correctly.” The issue has been fixed according to Microsoft for all unmanaged devices without the need for user intervention, although it may take up to 24 hours before the fix is rolled out to all systems. To speed up the process, you can reboot all potentially affected devices after downloading the above mentioned package.
What to do if your system is already damaged
For those who have already run chkdsk /f on their system, damaging the file system, you can try to restore the boot by performing some basic steps provided by Microsoft. However, it is not certain that the steps will lead to a full restoration of the systems functionality:
After a series of failed boot attempts, the system should be booted into the Recovery Console
From the Recovery Console select Advanced options
Select Command Prompt
Type chkdsk /f followed by the Enter key.
Wait for the storage drive scan to complete. Once complete, type exit followed by the Enter key.
The device should boot up as expected. If the reboot leads to the Recovery Console select Continue – Exit and continue with Windows 10
Once the steps are complete the system should reboot and once again scan the primary storage drive. Once completed the system operation should return to normal.