Windows crashes when NiceLabel software prints labels (Windows cumulative March update)


After you install March 2021 cumulative update for your Windows, you might have trouble printing to your printers. You might experience:

  • BSOD (Blue Screen of Death) with the stop error code APC_INDEX_MISMATCH for win32kfull.sys.

  • NiceLabel Designer, PowerForms, or Web Client freezes, then your computer restarts or shuts down.

  • NiceLabel Automation Service stops. Automation Manager throws an error: "Unhandled exception occurred while executing trigger: The operation completed successfully."

The error can occur in all Windows applications that use printer drivers. NiceLabel is just one of many affected applications.



Microsoft has already released new optional updates that correct the problem.

To apply a fix, do the following:

  1. Install the March update (yes, the one causing the BSOD).

  2. Install the "Out-of-band" update included in the "optional updates".

    To access the optional updates, go to Windows Settings > Update&Security > View optional updates.



    You might not see View optional updates link.In this case, click on the Check for updates button. If one or more optional updates are available, the View optional updates link will appear.

There are two updates you have to install. Each Windows version has different updates.


if you don't know your exact Windows version, you can check in Settings > System > About, or visit the Microsoft site.

  • If you have Windows 10, version 2004 or 20H2, or Windows Server, version 2004 or 20H2, the initial update is KB5000802 and is fixed by KB5001567 and KB5001649.

  • If you have Windows 10, version 1909, or Windows Server, version 1909, the initial update is KB5000808 and is fixed by KB5001566 and KB5001648.

  • If you have Windows 10, version 1809, or Windows Server 2019, version 1809, the initial update is KB5000822 and is fixed by KB5001568 and KB5001638.

  • If you have Windows 10, version 1803, the initial update is KB5000809. and is fixed by KB5001565 and KB5001634.

  • If you have Windows 10, version 1607, or Windows Server 2016, the initial update is KB5000803 and is fixed by KB5001633.

  • If you have Windows 8.1 or Windows Server 2012 R2 the initial updates are KB5000848 and KB5000800. They are fixed by KB5001640.

  • If you have Windows Server 2012 the initial update is KB5000847 and is fixed by KB5000840 and KB5001641.

  • If you have Windows 7 SP1 or Windows Server 2008 R2 the initial update is KB5000841 and is fixed by KB5000851 and KB5001639.


You can also download and install the update manually by visiting Microsoft Update Catalog site and entering the appropriate KB number. Download the correct update that matches the version of your operating system. This solution works temporarily, only till the next automatic updates. If the next updates still don't fix the problem, you have to manually install the downloaded KBs again.


When the problem was initially detected, we recommended removing the March update. This solution works temporarily, only till the next updates. If the next updates still don't fix the problem, you have to remove the March update again.

If you are hesitant to install the new update, there is a step-by-step guide published by Microsoft on how to resolve the problem. It requires some technical re-configuration of each driver and Windows application you use for printing. See the instructions here and the video here.