(Unreal Engine 5) How to fix: "Lighting Build Failed. Swarm failed to kick off. Compile Unreal Lightmass"?

Hi guys,

Been having multiple problems with the Lighting Build failing,
unsure of what the next steps should be.
After trying to compile lightmass in Visual Studio, it appears that there are certain files missing.

In the above image, the only file in this folder is a config file.

However, comparing it to a file I found on a YouTube fix, this is what they had on their screen:

Would anyone know what to do?

Hello Alcoholocaust, thank you for posting and welcome to the Unreal community.

Would you mind sharing the errors you receive when your lighting build fails?
Depending on if you are using the source build or getting the engine from the launcher, the cause of the concern could vary.

I found an older thread that discusses at length for both situations. Solutions range from rebuilding the lightmass module itself, using development editor mode in VS, and if you are using a version on UE from the launcher, you may have to check around your level for any errant meshes.

Please have a look as I found this thread most insightful.

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Hi Polite_Muon,

Thank you! I will look into the thread you shared.

Here are the errors I am getting:

Thank you for the reply Alcoholocaust and for the clarifying information.

Thankfully the warnings and errors are pretty straight forward.
If you go to your WorldSettings level and click build > LightingOnly, does that same error show up after the lighting is built?

If your lighting build fails, Dongas has a pretty nifty step-by-step solution, though it is for a much older engine version if you’d like to try.

For the warnings, I would try to remove those assets and place them back into your level or check the collision type.

I hope this and the other link I sent you earlier helps you resolve this.