Error while running the main xaml. System.TypeLoadException: Could not load type 'UiPath.Core.Activities.TaskAsyncCodeActivity

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1

when i try running the xaml this error pop up.

Error ERROR Validation Error System.TypeLoadException: Could not load type 'UiPath.Core.Activities.TaskAsyncCodeActivity1' from assembly 'UiPath.UiAutomation.Activities, Version=21.4.4.0, Culture=neutral, PublicKeyToken=null'. at Non_System.Non_System.GlobalErrorCheck.GetImplementation() at System.Activities.Activity.OnInternalCacheMetadata(Boolean createEmptyBindings) at System.Activities.Activity.InternalCacheMetadata(Boolean createEmptyBindings, IList1& validationErrors)
at System.Activities.ActivityUtilities.ProcessActivity(ChildActivity childActivity, ChildActivity& nextActivity, Stack1& activitiesRemaining, ActivityCallStack parentChain, IList1& validationErrors, ProcessActivityTreeOptions options, ProcessActivityCallback callback)
at System.Activities.ActivityUtilities.ProcessActivityTreeCore(ChildActivity currentActivity, ActivityCallStack parentChain, ProcessActivityTreeOptions options, ProcessActivityCallback callback, IList1& validationErrors) at System.Activities.ActivityUtilities.CacheRootMetadata(Activity activity, LocationReferenceEnvironment hostEnvironment, ProcessActivityTreeOptions options, ProcessActivityCallback callback, IList1& validationErrors)
at System.Activities.Validation.ActivityValidationServices.InternalActivityValidationServices.InternalValidate()
at System.Activities.Validation.ActivityValidationServices.Validate(Activity toValidate, ValidationSettings settings)
at System.Activities.Presentation.Validation.ValidationService.CoreValidationWork(ValidationReason reason, CancellationToken cancellationToken) Main.xaml

I am using Studio version - 2021.4.4
Uipath.system.activities - 21.4.0

I tried upgrading and downgrading the activity version. it doesnt help

2

Hello @sameer149167!

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3

@loginerror can you tell why this error occurs ?

4

It looks like a UIAutomation bug. I assume upgrading the UIAutomation package fixed the issue?

5

Hi Sameer, you probably already fixed this issue for yourself but for anyone that is encountering the issue now, I fixed this issue by checking all dependencies of the project itself and the libraries that I had in the project.
We got this error after a migration from on-prem to cloud and after re-compiling all library items and updating all packages to at least 2021.10+ the issue was fixed. The packages from the libraries were from 2019 and the studio was 2024.04 or something like that so this could have created the problem.