I have a SharePoint 2010 designer workflow that is running on change. When I publish a new version of the workflow and the items is edited, I end up with two version of the workflow running. Is there any way to stop this from happening?
In the workflow settings for your list/library, you should be able to select your first version of the workflow and set it to 'No new instances'. Workflows currently running of that version will continue, and new ones will be based off of the new workflow.
The answer above is correct. I will tell how to do it correctly. Go to your Library or List and on the top of the page go to "Library/List tab", "Workflow Setting", click "Remove Workflow", and make the adjusts above.