Issue
After migrating Nintex Forms from 2013 to 2016 all of the existing Nintex Forms are blank when opened.
Resolution
- Navigate to Central Administration > Application Management > Manage Web Applications > Select Web Application > Manage Features > Nintex Forms and verify that Nintex Forms has been activated on the Web Application.
- On the server hosting Central Administration open SharePoint Management Shell and run the following commands:
Install-NFServiceUpgrade-NFService