Regression Suite Automation Tool: System.Exception: Microsoft (R) Visual C# Compiler version 4.6.1586.0 for C# 5

I had a really annoying issue today…

We are starting use Regression Suite Automation Tool (RSAT) for test automation in Dynamics 365 for Operations. This tool is using Task Recorder, Business Process Modeller and Azure Devops for automatically testing process in D365FO.

I needed to install it for one of my colleagues and run into this error message when I was trying to regenerate test files for a test case:

[BITS D365 RSAT] Create party record (external)
System.Exception: An error occurred while generating test cases. See details below. —> System.Exception: Microsoft (R) Visual C# Compiler version 4.6.1586.0
for C# 5
Copyright (C) Microsoft Corporation. All rights reserved.
This compiler is provided as part of the Microsoft (R) .NET Framework, but only supports language versions up to C# 5, which is no longer the latest version. For compilers that support newer versions of the C# programming language, see

c:\Temp\XXXX\MyTestCase.cs(253,56): error CS0266: Cannot implicitly convert type ‘Microsoft.Dynamics.TestTools.Dispatcher.Client.DispatchedForm’ to ‘MS.Dynamics.TestTools.DispatcherProxyLibrary.MyForm.MyGrid’. An explicit conversion exists (are you missing a cast?)

— End of inner exception stack trace —

My thoughts was that there was something wrong with my Dynamics 365 FO VM and I could not get it to work… after several frustrating hours I read a Yammer post that indicated that it might be an issue with the actual test case… go figure I had been testing with the same test case every single time. Once I switched test case everything worked… That is great… Wohoo

That is it for today


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