FlexLogger Crashes With Exception 0x6AD7DF6F

Updated Dec 8, 2023

Reported In


  • FlexLogger

Issue Details

  • FlexLogger will occasionally crash and display error 0x6AD7DF6F: Unhandled Task Exception. I see the following message in the FlexLogger crash log:
ErrorId: 0x6AD7DF6F
Message: Unhandled Task Exception
Error message:
    Object reference not set to an instance of an object.
    Contact National Instruments to report this error
  • While trying to use FlexLogger's SystemLink Tag functionality, FlexLogger crashes with the error 0x6AD7DF6F: Unhandled Task Exception.
  • After trying to start my measurements on the Screen tab I am getting a FlexLogger crash with exception 0x6AD7DF6F: Unhandled Task Exception.
  • Anytime I click the RUN button FlexLogger crashes with error 0x6AD7DF6F.


These crashes can be due to different causes, use the following guide to evaluate your system and complete the troubleshooting steps accordingly:
  • The crash may be related to a Microsoft .NET Framework security update in your system, refer to this Microsoft's GitHub page article for more information about the potential symptoms and troubleshooting steps.
  • If you are receiving this error when trying to use the SystemLink Tag functionality in FlexLogger, it could be caused if you previously had FlexLogger 2018 R3 installed, and then upgraded to FlexLogger 2018 R4 or later. FlexLogger 2018 R3 included the SystemLink Tag functionality as a preview feature. In later versions of FlexLogger, this feature was fully enabled. Try the following to repair the SystemLink Tag functionality of your FlexLogger installation:
    1. Open NI Package Manager.
    2. Go to the Installed tab.
    3. Uninstall FlexLogger.
    4. Still in the Installed tab, uncheck the Products Only box.
    5. Click the gear Settings icon and check the box Show full version numbers and hidden packages.
    6. Enter "rabbit" into the search bar. Uninstall anything that shows up in that list. 
    7. Enter "erlang" into the search bar. Uninstall anything that shows up in that list.
    8. Go to the Windows Add or Remove Programs menu and search for the RabbitMQ server entry and OTP Erlang. Make sure to uninstall these as well if they are present. 
    9. Restart your computer.
    10. Reinstall FlexLogger.
  • If this error occurs under any other circumstances, complete the reinstallation of FlexLogger by following the previous steps, except steps 4 through 8 since these are only intended to remove the components related to the SystemLink Tag functionality.