Microsoft shares fix for Windows 10 BSOD error “APC_INDEX_MISMATCH”

Windows 10’s March 2021 cumulative updates are causing serious problems for some people and it’s still not clear how widespread the issue is. The problem was first reported by users of both Windows 10 consumer edition and Windows Server when their devices crashed abruptly with the “APC_INDEX_MISMATCH” stop error code.

In addition to blue screens, users reported that their printers are failing to fully print the documents, apparently due to some kind of compatibility issue in the March cumulative updates – although exactly why this problem is experienced wasn’t clear until today.

A Microsoft spokesperson has now confirmed that the company is aware of the Blue Screen of Death issues caused by the following cumulative updates:

• KB5000802 (version 2004/20H2)
• KB5000803 (Windows Server)
• KB5000808 (version 1909)
• KB5000809 (version 1809)
• KB5000822 (version 1803).

In these cumulative updates, there is a worrying “APC_INDEX_MISMATCH” and “win32kfull.sys” Blue Screen of Death bug.

Microsoft noted that the bug is hitting devices with Type 3 printer drivers only. It does not affect printer drivers that are Type 4. Before applying the cumulative updates, Microsoft recommends verifying the type of your printer driver:

1. Open Windows Search.
2. Type printmanagement.msc.
3. In the Print Management window, expand Print Servers.
4. Click on “computer’s name”.
5. Select Printers to see the Driver Type for installed drivers.

Before following the above steps, you must have the “Print Management Console” enabled in Windows 10. To enable the console, search for ‘manage optional features’ in Windows Search. On the optional features screen, click on ‘Add a feature’ and enable Print Management Console.

If you see Type 3 printer drivers in the Print Management Console, you should either skip the update or stay prepared for the Blue Screens.

Workaround for APC_INDEX_MISMATCH stop error

If you’re already using the latest cumulative update and you have got the blue screen problem, Microsoft recommends following these steps:

1. Open Command Prompt (elevated)
2. Run the following command after replacing “KX driver for Universal printing” with the name of your printer:

   rundll32 printui.dll,PrintUIEntry /Xg /n “KX driver for Universal printing”

3. The above command will open the printer user interface dialogue box. In the attribute field, if it does not say ‘direct’, run the following command to enable direct printing manually:

   rundll32 printui.dll,PrintUIEntry /Xs /n "KX driver for Universal printing" attributes +direct

4. Close the printing interface and Command Prompt.

Microsoft also confirmed that it’s working on another update and a solution will be available in the coming week.