Introduction
A "Value cannot be null" error may occur while editing SharePoint Item data or SharePoint Document data when the SharePoint Item or Document has a running K2 SharePoint Workflow Integrated Instance. The error occurs because association data has not been correctly set on the workflow association applied to the List or Content Type.Image

Workaround
The following steps describe how to manually re-associate the K2 Workflow with the SharePoint List or SharePoint Content Type:

Step 1
Navigate to the Workflow Settings page and click on the workflow that needs to be corrected

Image

Step 2
On the Change a Workflow page click on the “Next “ button

Image

Step 3
On the Workflow Association page click the “OK” button

Image
The K2 Workflow will now be re-associated with the SharePoint List or SharePoint Content Type and the error will no longer occur.