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

[KahPou_Liew (smallpotato)]

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)

[marci080]

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

NullReferenceException at the start of the process

I am getting a NullReferenceException at the start of the process. “Object reference not set to an instance of an object. This error usually occurs when using a variable with no set value (not initialized).” It does not point to any activity. The error points to the start of the process. I am not sure if this explains the error clearly. Please let me know if any additional information is needed. Thanks in advance [image]

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

[KahPou_Liew (smallpotato)]

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!