Ganesh - did you try to use the Complete Workflow Task action?  What is the business condition where you want to force approve the task?  When you attempted to delegate, what had previously occurred on the task?  Did someone have the open at the time of the delegation (or just before that)?

Regards,

Tom

Hi Ganesh,

you can find some information regarding this issue here: Task Lock - Task is locked by a running workflow and cannot be edited

I have experienced this issue myself a few times, and have a written a little powershell snippet to fix this issue, based on the code from Development Hole: Locked Workflow . The blog post is a bit older, but the solution still works for SharePoint 2013.

Hope this helps

Thanks Tom and Martin for your response.

Martin  - I will try the powershell and see if that works for me

Hi, your workflow is running on the workflow tasks list or on another library?

its running on a SharePoint list. No workflows attached to task list

A workflow could be stuck on that item. You may need to go into the workflow history and terminate some workflows.