My client recently upgraded their version of Nintex Workflow 2010 and suddenly some of my workflows started to fail on deployment.
The following error cropped up:
Error deploying workflow: Server was unable to process request. ---> An item with
the same key has already been added. ---> An item with the same key has already
A little digging unveiled the problem - I had two items in a 'Create Item' shape with the SAME DISPLAYNAME. I needed to move the second item to a new 'Update Item' shape in order for it to work.
I order to get the workflow to deploy, I had to manually remove the 'duplicate' item from the serialized XML. Hooray!!
It was then a simple matter of creating a new shape to update the 'duplicate' value.