Upgrading my project from 4.19.1 to 4.20 breaks simple move to location/actor

I converted my project from 4.19.1 to 4.20 using engine’s conversion dialog. I converted in place.

I noticed a few error messages in the output log regarding renaming the Engine.Navigation to something like NavigationSystemV1 in the DefaultEngine.ini. I tried renaming, and then I tried deleting that portion because I noticed in a 4.20.2 test project it was not even in there. So I don’t think having that section in the ini file affects it that much. In the test project (4.20.2) I tried Simple Move to Actor and it worked!, but in mine it does not.

As part of the upgrade I updated my Visual Studio 2017 to a newer version since it apparently was complaining when it needed to be rebuilt. However, I was still encountering the move to issue even after the project was built successfully. After some tinkering I then uninstalled Visual Studio 2017 and reinstalled it again based on Epic’s documentation just to see if that had an effect, but it was the same.

I also tried deleting some folders like the Binaries and Saved directories and then rebuild the project through visual studio. However, when I opened it the project from the .uproject file it needed to rebuild a dll. I don’t think I understand why the visual studio rebuild did not build the dll. I don’t think I know much about building correctly there. Perhaps this is the area where I was wrong.

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I clicked on Build->Rebuild Solution and there seemed to be no errors, but when I loaded the .uproject as stated before it still needed to build the dll.

I tried deleting the nav mesh and adding it back.

I tried rebuilding and cleaning my Visual Studio 2017 code. Note, the C++ classes were just created a long time ago and I do not use them anymore. They are just sitting there and I don’t think I came close to doing any navigation calls in there.

So the state of the world right now is that Simple Move To Actor works on a test project in 4.20.2, but it does not seem to work in my converted project.

I read in the upgrade notes that 4.20’s navigation system is now a separate module. Perhaps I am rebuilding the project incorrectly, or there is some file that still needs to be updated that references some old navigation behaviour.

The next thing I am thinking of doing is actually just debugging the Engine source code directly and attempt to see why it is not working. I am hoping to do this as the last resort, but I am pretty sure this should get me a lot closer to solving this. However, before that it would be nice if there was just some easy fix or something that I might have looked over. Please help! Thanks.

Project Settings > Navigation Mesh > Runtime > Runtime Generation: set to Dynamic (from Static)

I am not 100% sure that this will fix your issue, but your issue sounds like my issue and it fixed it for me. This beautiful person named acxsasx figured it out.

https://forums.unrealengine.com/development-discussion/c-gameplay-programming/1520196-navigation-changes-from-4-19-to-4-20

Thanks a lot for responding! :). Once I attempt another upgrade I’ll give this a shot and hopefully it works!

Works for me. Thanks.

It turns out in my case I did not perform the step from here Unreal Engine 4.20 Release Notes | Unreal Engine Documentation where it says to run “This Python (3.5) script”. When I ran that it output a bunch of different files and the lines that needed to be updated.

I am sorry for not checking something like this.