Hi, we are working on test upgrading Nintex Workflow 2010/2013
In 2010 farm we use NWadmin operation detachDatabase to detach NW2010DB before migrating to 2013 farm. In 2013 all works fine after apgrade
Now the question is how we can attach NW2010DB back in 2010 farm to recover 2010 farm in work state?
You can use UI option to attach your database.
Please go to Nintex workflow management -> Database setup -> add a content database and use "Connect to an existing database" option form the page.