Fatal error: attempt to build nav collision data

I simply imported a default model into the engine from Blender. Then when I tried to launch the game, this message shows up every time, and I could not launch the game. Could anyone tell me how to fix this?

Same error on my site. After importing a downloaded mesh.

Hi Nuke. I found a way to solve this problem however I’m not sure if it is a correct method to do. I deleted the “saved” folder under your project in Unreal engine 4 folders, then I tried to launch it, the error is gone.

Hi ALTWang. Thanks for your comment. My error is also gone. But I did not do anything. Just shut down the PC and next day after launching UE4 again the error was gone. I don’t know what was the issue. But if I’ll have this error in future again I will remember your approach and give it a try :slight_smile:

Hi Nuke! Thank you! I will try this way to see if it works on my levels.