SP2010 Workflow Error - Task is currently locked by a running workflow and cannot be edited

Question

We have a Infopath library in SharePoint 2010 with multiple approval workflows running on the library.

Recently, most of the approvers are getting the below error while trying to approve their tasks.

Why are the tasks getting locked suddenly and how to fix it? I have been struggling with this for last couple of days.

Answer 1

This is a generic error in the SharePoint task workflow. "This task is currently locked by a running workflow and cannot be edited" is a common message which is seen when an error occurs while the SharePoint workflow engine is processing a task item associated with a workflow.

When a workflow processes a task normally, the following sequence of events is expected to occur:

1. The process begins.
2. The workflow places a ‘lock’ on the task so nothing else can change the values while the workflow is processing.
3. The workflow processes the task.
4. The lock is released when the task processing is finished.

When the message is encountered, it usually indicates that an error occurred between steps 2 and 4. As a result, the lock is never released.

Therefore, the ‘task locked’ message is not an error itself, rather a symptom of another error - the ‘task locked’ message does not indicate what went wrong. In most cases, once this message is encountered, the workflow cannot be made to continue and must be terminated and started again.

Possible reason for the error:

Modifying the task list

A cause of this error appearing consistently the first time a user tries to respond to a task is a modification to the default task list schema. For example, changing the ‘Assigned to’ field in a task list to be multiple selections will cause the behavior.

Parallel simultaneous responses

A cause of this error appearing inconsistently is multiple users responding to tasks in parallel at the same time. In this scenario, one task will complete correctly and the other will not process. When the user tries again, the ‘task locked’ message will display.

Additional processing on the task

A cause of this error appearing consistently and inconsistently is having an additional system running on the items in the task list. Some examples include; a workflow running on the task list, an event receiver running on the task list or another automated process querying and updating workflow tasks.

Possible Solutions:

First, approach just try to restart the SharePoint timer job service and see.

If that does not work follow the below steps:

• Log into SharePoint Central Administration
• Click on "Monitoring" link
• Underneath the "Timer Jobs" section click on the link "Review job definitions"
• Look for a job called "Workflow" (you may need page through using arrows at the bottom to get to the last page of job definitions)
• The job definition workflow possibly in the disabled mode. Click on the link "Workflow", we might see that the last time the job ran was right before we made updates.Set the job to run every 5 minutes and enabled.

Source:

Task Lock - Task is locked by a running workflow and cannot be edited