Chkdsk doesnt clear dirty bit afte win update

Hi steve,

Usually Chkdsk can remove dirty bits, but it has to be run properly. The auto or alert runs of chkdsk only produces an alert and really doesn't fix the bit. It is doomed to repeat the scan alert on next boot. In order for chkdsk to fix the dirty bit you have to tell it with a command modifier. Before I give you the instructions you should understand that this process can take a long time depending on the size of the HDD, but you must stick with it as quitting in the middle can cause more damage than you have now. Also when entering commands into the command prompt it must be exactly as I have written because the spaces and no spaces between letters in the command do make a difference. If an unknown command error returns then you typed it in wrong.

Click on Start then in the search box type cmd. The search list above will display cmd.exe under Programs.
Right click this cmd.exe and select Run as Administrator.

The command prompt window will open.
Type fsutil dirty query c: (the c is the letter of the boot drive so if your boot drive is a different letter then use that letter). This queries the drive, and more than likely it will tell you that it is dirty.

Next, type chkntfs /x c: . The x tells Windows to NOT check that particular drive on the next reboot.

Now reboot your computer using Windows> Reboot, it should not do a chkdsk and should take you directly to normal Windows login.


Once Windows has fully loaded, bring up another Command Prompt with Run as Administrator as you did above.

Type at prompt chkdsk c: /r . Answer Y when it asks if you want this to happen on the next boot. This should take you through 5 stages of the chkdsk scan and will unset that dirty bit. This can take an hour or more depending on the size of your hard drive, be patient and let it complete.

Once booted back to Windows, open another Command Prompt as Administrator like above.

Enter fsutil dirty query c: and Windows will confirm that the dirty bit is not set on that drive.

There are times when this doesn't work, but that usually is because the dirty bit problem is hardware based and the drive is going out. Yours seems more likely to be caused by software conflict and chkdsk usually can fix these dirty bits.

Hi steve,

I would do the repair chkdsk again now that you have uninstalled that bad Windows update. Chkdsk might be able to reset it now that the cause is gone.

If the error is stiil present, then there still are a few things we can do.

One option is to run Windows SFC utility which might be able to repair the Windows files that were munged by the update.

Another option is if all seems OK, you can set Windows to not run auto chkdsk at boot and thus no dirty bit notice.

See if the chkdsk fixes the problem after the update removal first and then we can consider these other options.