[UE4 - Promoted Build - 4.12.0] SwarmAgent failed to kick off ->Unrealightmass.exe missing

Development Getting Started & Setup
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Hi community!

I’m using UE4 from promoted build, currently 4.12.0 and was never able to build any Scene (since promoted 4.11 maybe, I don’t remember :wink: due to the “SwarmAgent failed to kick off…” issue until spotting this line in the logs:

[Interface:CacheAllFiles] Failed to cache the executable: C:\My\Path\To\GitHub\UnrealEngine\Engine\Binaries\Win64\UnrealLightmass.exe

Surprisingly, the executable was not present there so I’ve opened the VS Solution to build the UnrealLightmass Project to generate it. Now it runs fine…the lighting build is back so it would be nice to activate this project by default in the Engine Build Solution if this functionality is still required by the Editor right?

Note: VS 2013 and 2015 are both installed on my machine. In this situation, the current GenerateProjectFiles.bat still create VS 2013 solution if VS 2013 is installed so I just create a bat shortcut with the -2015 arg to generate VS 2015 solution. It would also be nice to remove VS 2013 logic from the Setup now :wink:

2

Hi Tensa_Zangetsu -

Thank you for your report, I was able to reproduce this issue and reported it as UE-25666. I will keep you informed as we continue to investigate a solution

Eric Ketchum

3

I just wanted to add that I’m also experiencing this, using 4.12.0 that I compiled myself.

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I’m getting the same issue with 4.11.1 from Github. Manually kicking off the build for unreallightmass.exe fixed it, even though the original build said everything succeeded.