Thanks for the post! I just upgraded my project to 4.26.1 and my navigation wouldn’t build during runtime, but it would if running in the editor. Every part of my project is dynamic and nothing can be pre-generated, I’d checked over the official documentation and other forum posts but nothing seemed to push the engine to build nav data after packaging. After manually changing the file you suggested it seems clear the editor doesn’t save a few options because it started working. I found out there’s 3 different locations of the navigation settings, only 1 can actually be changed:
DefaultEngine.ini* > Unreal Settings Menu > Spawned Nav Data*
Each of those have the exact same navigation settings and each get overridden if the parent doesn’t match (for some reason). In my case, the ‘dynamic’, and the ‘main nav data’ setting. If you have an issue with dynamic navigation, navigation invokers, or just moving obstacles, try changing the appropriate navigation values for your project in the DefaultEngine.ini file, then re-package.