Upgrade from 4.0 to 2011 workflows canceled

Question

So after upgrading from 4.0 to 2011 some workflows have been canceled and here's the error message when viewing the details.

Workflow instance cancelled during upgrade because it cannot be deserialized. A possible reason for this failure is a workflow referencing a custom activity that has been unregistered

Searching turns up zilch.

Looking in the database the above message is in the friendlyname column and checking the message column, where the full error is stored is null.

I would like to know if/how I can restart them to pickup where they left off?

Answer 1

Short answer no, once a workflow is cancelled it stops and cannot be re-started. However, if you fix the problem you can re-run them from the begining.

EDIT: you need to re-register and possibly make changes to your plugins before you can do this then.