I have a task assigned to a Approver in SP 2013 workflow. I want to auto approve the task after a certain period of inactivity using the workflow. I am setting the below fields on the task item

Set Task Outcome to Approved
Set Task Status to Completed
Set % Complete to 1

But the workflow is throwing the following error, when I check the outcome return value if outcome equals Approved

Input string was not in a correct format. at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)

How can I auto approve a task?


2 Answers 2


since this way was throwing error, i used REST API to achieve the auto approve/reject the task. i followed the below links to get this done

Updating list items using SharePoint 2013 workflow engine

Approve workflow tasks using REST API in SharePoint 2013

Hope this helps someone


This can be done by using a Second workflow (WF) on the task list, but the second WF does need to be a SP2010 WF not SP2013 WF.

Related Question: How can you do task auto approval in SharePoint Designer workflow after their respective due date

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