FlexLogger Crashes with Exception 0x6AD7DF6F

Updated Jun 25, 2020

Reported In


  • FlexLogger
  • FlexLogger 2019 R2

Issue Details

  • FlexLogger will occasionally crash and display error 0x6AD7DF6F: Unhandled Task Exception. You may 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.


  • These crashes may be related to a Microsoft .NET Framework security update detailed. Refer to the steps in Microsoft's KB to determine if this applies to your system and to find steps to resolve the issue.
  • 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.