Unreal Editor: "Light Build Failed. Swarm failed to kick off." OS X

When trying to build lighting, the following popups are displayed in quick succession in the editor:

Kicking off swarm
Light Build Failed. Swarm failed to kick off.

Environment:

  • Operating System: OS X 10.9.3
  • Version: 4.2.0-0+UE4 (built from github)

Hardware:

  • Processor: Intel Core i7
  • Video cards: Intel Iris Pro, NVIDIA GeForce GT 750M (2GB)
  • Memory: 16GB

Editor log:

[2014.06.06-21.20.54:320][ 82]MapCheck: New page: Map Check
[2014.06.06-21.20.54:432][ 82]Cmd: MAP REBUILD ALLVISIBLE
[2014.06.06-21.20.54:432][ 82]LogEditorServer: Rebuildmap Clear paths rebuilt
[2014.06.06-21.20.54:501][ 82]LogInstancedFoliage: Map Rebuilt - Update all BSP painted foliage!
[2014.06.06-21.20.54:506][ 82]LightingResults: New page: Lighting Build - Jun 6, 2014, 1:20:54 PM
[2014.06.06-21.20.54:543][ 82]LogStaticLightingSystem: Running Lightmass w/ ImmediateImport mode ENABLED
[2014.06.06-21.20.54:543][ 82]LogStaticLightingSystem: Running Lightmass w/ ImmediateProcess mode ENABLED
[2014.06.06-21.20.54:543][ 82]LogStaticLightingSystem: Running Lightmass w/ Sorting mode ENABLED
[2014.06.06-21.20.54:543][ 82]LogStaticLightingSystem: Running Lightmass w/ Mapping paddings ENABLED
[2014.06.06-21.20.54:543][ 82]LogStaticLightingSystem: Running Lightmass w/ Mapping debug paddings DISABLED
[2014.06.06-21.20.54:582][ 82]LogEditorBuildUtils: Build time 0:00:00

Looking through the source, I believe the editor is trying to execute “UnrealLightmass”. When trying to run this from the command line I get this following error. When I search from the Engine folder, I cannot find this dynamic library:

afuzzyllama-mbp:Mac afuzzyllama$ ./UnrealLightmass
dyld: Library not loaded: @executable_path/../../Plugins/Messaging/UdpMessaging/Binaries/Mac/UnrealLightmass-UdpMessaging.dylib
    Referenced from: /Users/afuzzyllama/Development/Unreal/Github/UnrealEngine/4.2/Engine/Binaries/Mac/./UnrealLightmass
    Reason: image not found
Trace/BPT trap: 5
afuzzyllama-mbp:Mac afuzzyllama$ ..
afuzzyllama-mbp:Binaries afuzzyllama$ ..
afuzzyllama-mbp:Engine afuzzyllama$ find . -iname "UnrealLightmass-UdpMessaging.dylib"
afuzzyllama-mbp:Engine afuzzyllama$

Not sure if this is related, but when I tried to run the SwarmAgent.exe with mono from the command line, I receive the following error:

Missing method get_IsNetworkDeployed in assembly /Users/afuzzyllama/Development/Unreal/Github/UnrealEngine/4.2/Engine/Binaries/DotNET/SwarmAgent.exe, type System.Deployment.Application.ApplicationDeployment
Unhandled Exception:
System.IO.FileNotFoundException: Could not load file or assembly 'System.Deployment, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies.
File name: 'System.Deployment, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
[ERROR] FATAL UNHANDLED EXCEPTION: System.IO.FileNotFoundException: Could not load file or assembly 'System.Deployment, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies.
File name: 'System.Deployment, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

Same issue with 4.1.1. I don’t have the issue with other maps.

I managed to get out of trouble by; Copy the content of the level (without the light) create a new empty level, past the content and start to build. If swarm works, you now have ‘unlocked’ the bug and can go bake light back in the main level.

@Eric Ketchum - What specs do you need? Also, how do I know if I’m attempting to build with more than 1 CPU/over the network? I’m just trying to do this through the “Build” button in the editor.

Hi afuzzyllama -

Can you provide us your system specs and whether you are attempting to build lighting using more than 1 CPU or over a network?

Thank You

Eric Ketchum

Eric - I’ve added the specs to the question.

Hi afuzzyllama -

What is your processor, video card and memory specifications and if all you are doing is hitting the build then you are not building over a network or with more CPU, it has to be setup to do this.

Thank You

Eric Ketchum

Hi afuzzyllama -

We are still tracking down this issue, but I want to ask are you having any memory related errors separate from the Swarm agent error. And can you let me know the exact Changelist you are using from GitHub?

Thanks for your help and patience -

Eric Ketchum

I downloaded the zip from the github on June 4th. I do not have commits after that date (looks like 6th, 9th, and 10th) in my code base. Thanks for the update.

What particular memory related errors are you thinking of? I get memory related errors all the time, but that is in my own C++ code and not the engine I believe.

Unfortunately, it seems like Required zips are missing the UdpMessaging plugin for Mac. We should update them soon but in a meantime you can solve the problem by building UnrealLightmass yourself in Xcode.