Error - Object reference not set to an instance of an object

I am keep getting this error whenever run any process even the simple write line activity.

Need someone help on it ASAP!! Thanks in advanced.


Below is the detail:
An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is:
System.NullReferenceException: Object reference not set to an instance of an object.
at UiPath.Core.GenericValue.op_Addition(GenericValue value1, GenericValue value2)
at lambda_method(Closure , ActivityContext )
at Microsoft.VisualBasic.Activities.VisualBasicValue1.Execute(CodeActivityContext context) at System.Activities.CodeActivity1.InternalExecuteInResolutionContext(CodeActivityContext context)
at System.Activities.Runtime.ActivityExecutor.ExecuteInResolutionContext[T](ActivityInstance parentInstance, Activity1 expressionActivity) at System.Activities.Variable1.PopulateDefault(ActivityExecutor executor, ActivityInstance parentInstance, Location location)
at System.Activities.ActivityInstance.ResolveVariable(Variable variable, ActivityExecutor executor)
at System.Activities.ActivityInstance.ResolveVariables(ActivityExecutor executor)
at System.Activities.Runtime.ActivityExecutor.ExecuteActivityWorkItem.ExecuteBody(ActivityExecutor executor, BookmarkManager bookmarkManager, Location resultLocation)

Hi @KahPou_Liew

Are you using any Variables or Arguments in your Flowchart?
If you do, try providing initial/default values for them.
Basically, the NullReferenceException occurs when you access those variables that are NULL (= not set to an instance).

Your query is similar to this one so please check this for more hints

If the problem persists, we could help you more if you provide the xaml or screenshot of the logs/local pane.


Appreciate your suggestion given. This was solved after I changed all the variables type from “Generic Value” to the variables type which the variable should be! Thanks again!


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