As always, Microsoft released new updated for all supported versions of Windows 10 on the second Tuesday of the month, a day affectionately referred to as Patch Tuesday. Unfortunately, these updates ended up being problematic in a big way, causing a bug that left users with a blue screen of death (BSOD) when they tried to use a printer. After offering a temporary workaround over the weekend, the fix is now here in the form of an out-of-band cumulative update. In these updates, there is just one fix, which “addresses an issue that might cause a blue screen when attempting to print to certain printers using some apps and might generate the error, APC_INDEX_MISMATCH.” In other words, this update is pretty straightforward. It should be available for anyone affected – specifically those on Windows 10 versions 1803, 1809, 1909, 2004, 20H2, and Insiders on 21H1 – but it’s not going to be installed automatically. If you go to Windows Update and check for updates, you’ll see that there’s a new optional update, which will look just like a C week update. That’s the one that you’ll need to fix the issue. The regular C and D week updates will arrive later on this month, and Microsoft has already said that those are going to remove the old Edge browser, so we know they’re coming. Any future cumulative updates will also include this fix.

Update: Microsoft has released out-of-band non-security updates to address the Windows 10 printing crash issue.

Microsoft has provided a temporary fix for the Windows 10 blue screen crashes plaguing customers when printing after installing the March 2021 cumulative updates. Redmond confirmed the known issue causing Windows 10 BSOD crashes after BleepingComputer reported a wave of user complaints regarding system crashes when printing. After installing the updates released during this Patch Tuesday, “you might receive an APC_INDEX_MISMATCH error with a blue screen when attempting to print to certain printers in some apps,” Microsoft explained. “We are working to resolve an issue impacting a subset of customers using certain printers,” a Microsoft spokesperson told BleepingComputer. Platforms affected by Windows 10 BSOD crashes include the following both client and server versions running March 2021 cumulative updates:
  • KB5000802: Windows 10 2004/20H2 & Windows Server 2004/20H2
  • KB5000808: Windows 10 1909 & Windows Server 1909
  • KB5000822: Windows 10 1809 & Windows Server 2019
  • KB5000809: Windows 10 1803 & Windows Server 1803
According to Microsoft, this issue “affects a subset of Type 3 printer drivers and does not affect printer drivers that are Type 4.” Use the steps available here to find the printer driver type installed on your system.

Official workaround available

While Microsoft is investigating the crash issues and is working on an update, you can uninstall the offending updates following the steps described here to restore printing functionality and get rid of the blue screen errors. However, if you don’t want to remove the security updates deployed with the March cumulative updates, you can use an official temporary fix provided by Microsoft to mitigate the issue. While Microsoft provides a video detailing the workaround instructions, but we’ve also detailed the steps below the embedded video. To print from 32-bit apps (e.g., Acrobat, OpenOffice) on 64-bit Windows versions without crashing, Microsoft recommends enabling Direct Printing for your printer using the following procedure:
  1. Open an elevated command prompt and run the following command to find if the feature is already toggled on (replace PRINTERNAME with the name of your printer):
    • rundll32 printui.dll,PrintUIEntry /Xg /n PRINTERNAME
  2. If Direct Printing is not enabled, run the following command from the same elevated command prompt (replace PRINTERNAME with the name of your printer):
    • rundll32 printui.dll,PrintUIEntry /Xs /n PRINTERNAME attributes +direct
To print from 64-bit apps on 64-bit OS or using 32-bit apps on 32-bit OS, you have to download and install the Application Compatibility Toolkit to apply the PrinterIsolationAware fix to affected applications using the Compatibility Administrator tool.