Getting error while opening an existing project


Could not find type ‘IsTrue’ in namespace ‘’. Row: 334, Column: 28

already installed all the available packages which includes Microsoft.Activities.Extentions Can anyone tell what else could be done.


I got this error when I moved my project to a different machine. Check if you have any package updates or try uninstalling Microsoft.Activties and resintalling it.


Thanks. It worked


I also have same issues. The error message :
“message”: “System exception. Retry: 0. Cannot create unknown type ‘{}SplitString’. at Source: Invoke workflow file: UiPath.Core.Activities”,
try uninstalling Microsoft.Activties and resintalling it, but it does not work. Have any idea to solve?


I think you are trying to open a project/workflow built with a newer version of studio, on an older version of studio that does not have all the activities used in the project/workflow