Unreal Lightmass executable is outdated

Development Rendering
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1

After doing a custom compile of latest 5.1 preview editor source and trying to build my lighting I get the following warning

Warning: Failed to build lighting!!! Unreal Lightmass executable is outdated. Recompile UnrealLightmass project with Development configuration in Visual Studio.

Anyone know how to solve?

2

Yo
Same issue, did u find a fix?

Do this to fix it >

./UnrealEngine_Repo_dir/Engine/Build/BatchFiles/Linux/Build.sh UnrealLightmass Linux Development -verbose

use Win64 instead of Linux if u on windows.

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Happened for me too after building UE 5.1 for macOS as described in Github Readme. Fix:

  • Go to UnrealEngine/Engine/Build/BatchFiles/Mac
  • Exec: ./Build.sh UnrealLightmass Mac Development -verbose
8 Likes
4

This worked for me: Debugging lightmass - Gamedev Guide

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On Windows:

  • Open Powershell
  • Navigate to UnrealEngine\Engine\Build\BatchFiles
  • Enter command " ./Build.bat UnrealLightmass Win64 Development -verbose "

Worked for me.

34 Likes
6

Hey there,
If you are on Windows 64 bits, do the following to fix the issue:

Go to your UnrealEngine folder then Engine>Build>BatchFiles

then open cmd there and type the following command:

Build.bat UnrealLightmass Win64 Development -verbose

and wait then try again, it worked for me :slight_smile:

8 Likes
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Thanks, work fine…

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For me too, thanks

9

thanks

1 Like
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Nice!

11

nice, that works for me too

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It worked for me too, thanks a lot !

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Thanks!

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For anyone else stumbling onto this problem with UE 5.x using a source build:

The old UE4 workflow was that the UnrealLightmass project was included as a project in your game project source, and you could just build it from your game project.

In UE5.x, the UnrealLightmass project is now included exclusively in your UE5 solution. You won’t find it in your project solution. So, just open up the UE5.sln file in visual studio, then in solution explorer, you navigate to “Programs → UnrealLightMass”, right click and “build”.

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Thanks，it worked for me too