20.4.3
Object reference not set to an instance of an object.

Unable to start execution: System.NullReferenceException: Object reference not set to an instance of an object.
at UiPath.Studio.Plugin.Workflow.Shared.Project.ProjectItems.Process.WorkflowFileProjectItem.<>c__DisplayClass7_0.<.ctor>b__0()
at System.Lazy 1.CreateValue() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Lazy 1.get_Value()
at UiPath.Studio.Shared.Validation.ValidableItem.GetValidator()
at UiPath.Studio.Shell.Services.ProjectValidationService.d__8.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at UiPath.Studio.Plugin.Workflow.Execution.Services.ExecutionValidationService.d__6.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at UiPath.Studio.Shell.Execution.Services.ExecutionManagerBaseService.d__58.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at UiPath.Studio.Shell.Execution.Services.ExecutionManagerBaseService.d__57.MoveNext(), HResult -2147467261

Usually this means that you are trying to access a variable which has no value in it. When the value is null you get this exception message.

As @jack.chan said, debug through your process to see which activity fails and then look for all the input variables used by that activity and check if you missed allocating value to it.

Hello @MARILENE_ANG_JIA_XIN ,

Usually you will get this error if no default value is prvided or not initialised properly. Please go to debug->Step Into. Enable "Hghlight ement " also.

Then you can understand in which activity you are getting the issue. Please check whether you are using some variables inside that activity or plz share the screenshot here.

@MARILENE_ANG_JIA_XIN

Are you using any variables which is the type of data table . If that is the case can you go to that variable name (in variables panel) and in the default value pass the below exp

New System.Data.DataTable
              
Hi @ushu,
That won’t solve the problem. Allocating a new empty datatable may continue to give you errors like rows not found when the variable is further processed.
The ideal way to solve this issue is to ensure the value allocation is made correctly to the variable by debugging for the root of the cause.
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