Microsoft .NET error


I'm using Navigator v8i(SELECTseries 6) Version When I try to use the keyin "markup export all" or "markup export active" I get a Microsoft .NET Framework error. I attached a screenshot of the error message. This issue was also replicated on another laptop with a different model using Navigator v8i(SELECTseries 4) Version . The same error message occurs.

It's running on a Windows 10 machine with all the latest Windows updates. I've already tried running the .NET repair tool and installed the latest version of the .NET framework. Navigator itself was also uninstalled and reinstalled. 

Does anyone have any suggestions for troubleshooting? 

Best regards,