Hi,
So I’ve recently tried learning unreal engine but I can’t build light. Whenever I click it, it pops up with Lighting build failed when I open up the swarm agent it says “Error: invalid class”. I’ve gone through questions similar to this but nothing has worked so far. Heres a list of the stuff I’ve tried:
-Redownloading the engine.
-Changing my internet connection.
-Cleaning and validating swarm cache
-checking Force No Precomputed Lighting is off
It happens on every map that I click build on, so it’s not an isolated incident. Any help or suggestions are appreciated.
Greetings @Damander228 !
We see that this is your first time posting in our forums! Welcome to the Unreal Engine community! 
Although we are very excited that you have recently starting using UE, we’re so sorry you’re having issues with lighting. We deeply appreciate you posting your issue here and including the steps you took to try to resolve it on your own. The more detailed you are, the more information the community has to know how best to assist you. Until someone with a higher level of expertise responds, I do want you to know that you are part of an awesome community, and we so stoked to have you as a member! I wish you the best of luck in a resolution to your lighting issue. 
Something that might help is I just clicked Validate data it came up with an error:
/Engine/Tutorial/InWorldBlueprintEditing/TutorialAssets/IWBE_Blutility contains invalid data.
And then when I open it up and try to compile the blueprint it can’t compile and in the compiler results, it says 1 Fatal issue(s).
I’ve fixed it now and I did this by resetting my computer.
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Hi @Damander228 !
I’m so happy to learn that you’ve found a simple fix for the issue you were having! 
Thank you for sharing!