Windows 10 emergency updates released to fix printing crashes

Microsoft has released non-out of band security updates to address a known Windows 10 issue that causes blue screens when printing to network printers after installing the March 2021 cumulative updates.

According to Microsoft, the cumulative updates released today resolve “an issue that could cause a blue screen when trying to print to certain printers using certain applications and could generate the APC_INDEX_MISMATCH error.”

Cumulative updates containing the hotfix released today are released as optional updates so that they are not automatically installed through Windows Update.

To install updates manually, you will need to open Windows Update and “Check for Updates”. You can then click directly on a link to download and install the update or go to the “Optional updates available” area and select it from the list.

Updates can also be downloaded manually from the Microsoft Catalog using the following links:

After installing this update, Windows 10, version 2004 will be updated to build 19041.868 and Windows 10, version 20H2 to build 19042.868.

Affected Windows printers and platforms

Printer brands affected by this known issue include Kyocera, Ricoh, and Dymo.

Microsoft has confirmed the known issue causing Windows 10 BSOD crashes after BleepingComputer reported on a wave of user complaints about system crashes while printing.

Since then, there has been a constant stream of complaints that printing causes Windows 10 to crash with an “APC_INDEX_MISMATCH for win32kfull.sys” blue screen.

Microsft states that this problem “affects a subset of Type 3 printer drivers and does not affect Type 4 printer drivers.” To find the type of printer driver installed on your system, follow the steps available here.

The platforms affected by this issue include the client and server versions of Windows:

• Client: Windows 10, version 20H2; Windows 10, version 2004; Windows 10, version 1909; Windows 10, version 1809; Windows 10 Enterprise LTSC 2019; Windows 10, version 1803
• Server: Windows Server, version 20H2; Windows Server, version 2004; Windows Server, version 1909; Windows Server, version 1809; Windows Server 2019; Windows Server, version 1803

The cumulative updates causing Windows 10 blue screens when printing are:

• KB5000802 for Windows 10 2004 / 20H2 and Windows Server 2004 / 20H2
• KB5000808 for Windows 10 1909 and Windows Server 1909
• KB5000822 for Windows 10 1809 and Windows Server 2019
• KB5000809 for Windows 10 1803 and Windows Server 1803

Those who cannot immediately install the out-of-band cumulative updates released today can apply a Microsoft-shared workaround over the weekend.