Error in core activities

Studio version in personal laptop 2017.1. Robot version 2018.2.6 in QA. Process runs fine in laptop. When i move it to orchestrator and run in the BOT attached with 2018 version i get this error:

  • Info: “Execution error : System.Xaml.XamlObjectWriterException: Cannot create unknown type ‘{}DeserializeJson({clr-namespace:Newtonsoft.Json.Linq;assembly=Newtonsoft.Json}JObject)’.\r\n at UiPath.Core.Activities.InvokeWorkflowFile.EndExecute(AsyncCodeActivityContext context, IAsyncResult result)\r\n at System.Activities.AsyncCodeActivity.System.Activities.IAsyncCodeActivity.FinishExecution(AsyncCodeActivityContext context, IAsyncResult result)\r\n at System.Activities.AsyncCodeActivity.CompleteAsyncCodeActivityData.CompleteAsyncCodeActivityWorkItem.Execute(ActivityExecutor executor, BookmarkManager bookmarkManager)”

Please be informed that UiPath.Core.Activities package has been split into below two -

UiPath.System.Activities and UiPath.UiAutomation.Activities in 2018.3


This is most likely due to your Dependencies found in the project.json have an activity version that is not found in the feeds that the Robots are looking at.

Those feeds are found in the NuGet.config file at “C:\Program Files (x86)\UiPath\Studio”
And, they should be set for each Robot, so if you use a Community Feed, you would want that in there as well.

In order to solve this you will need to go to your development machine and ensure the correct package is installed from those specific feeds (usually Local). It’s probably the UiPath.Web.Activities.

You want to make sure that you have the version found in the Available is installed, because if it is not, then the Dependencies won’t match with the Robots. After installed the correct version, then Publish the project again to regenerate the project.json file. Verify that the .json file has the correct version number.

For any other packages that have this issue, you will need to do the same. Also, sometimes you need to delete the dependencies from the .json, Save it, then Publish it so it can regenerate the correct Dependencies (although, I don’t know if this is really needed)

EDIT: you might need to use the packages in the Gallery too as Local means it’s only found on that specific machine.

I’m hoping this will help resolve the problem.


i am trying to install the version 1.1.6479.13209 and after successful installation when i close the studio and open again it goes back to old version again

I think I’ve seen that before. Did you try going to the Installed section and uninstall it first, then restart Studio? Then, go back to Available to install.

Yes i did that

Unfortunately, I can’t remember what I did exactly the last time I saw that.

You could see if technical support can possibly walk you through some solutions.

try search the package newtonjson and reinstall