Could not load file or assemlby "System.Activitivites"


Getting error while installing custom activity package created in VS2022.

Could not load file or assemlby “System.Activitivites”

1 Like


It may be better to use UiPath.Workflow.Runtime 6.0.0-20220909-01 instead of 6.0.3 in your project. Can you try this?



Could you please provide your code with package references from .Actrivities.Design csproj file?
Something like this:

And make sure your target framework is net6.0-windows (You are using activity creator v4)


I have degraded the dependacy and created new package, it’s installed successfully. But the activity is not showing in studio Activities panel.

Ok, check if there is a new nuget file after publishing

I really wish UiPath would fix all the problems in v4 (v5?) instead of everyone having to share work arounds. It doesn’t work near as good as the v3 (Windows-Legacy) version and they keep pushing that Windows-Legacy will be depreciated.

  • The template can’t create a project if you don’t EXPLICITLY have .Net Framework 4.6.1 installed, even though it’s not used.
  • The v4 looks for the older supporting libraries (beta) instead of the current versions.
  • The template doesn’t default to build NuGet files in a “._nuget” folder
  • Heck, it fails to compile all projects after adding the first activity.

Come on UiPath. Step up the game please.