Where to find the reference System.Activities when creating a Custom Activity ?
Resolution: The System.Activities.dll can be found in the .NETFramework folder,
C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\<Framework version>
Additionally, check if the Dll is found in the below 2 locations as well:
- C:\Windows\Microsoft.NET\Framework\<Framework version>
If the System.Activities.dll is still missing, try repairing or reinstalling .NET.
Use the Microsoft .NET Framework Repair Tool to repair all installed versions of .Net Framework.