Can't build lighting "MapCheck:Error: Error WorldInfo_0 Maps need lighting rebuilt"

Hi!
I had just downloaded 4.13 preview 3 and upgraded my original 4.12 project, however I cannot seem to build lights at all.
It will instantly fail and the error “Lighting build failed. Swarm failed to kick off” will pop up.
I have tried building lights with a default, new project in 4.13 and that works fine, however my project level seems to be the issue. In 4.12 it had successfully built and I had not made any changes to the level besides upgrading it.
From what I can see the only error in my output log is “MapCheck:Error: Error WorldInfo_0 Maps need lighting rebuilt”, but this seems to be the reason why my light build will fail…

This is what shows in the output log:
“LightingResults: New page: Lighting Build - 26 Aug 2016 1:17:17 am
LogSwarmInterface: [OpenConnection] Registering TCP channel …
LogSwarmInterface: [OpenConnection] Connecting to agent …
LogSwarmInterface: [TryOpenConnection] Testing the Agent
LogSwarmInterface: [TryOpenConnection] Opening Connection to Agent
LogSwarmInterface: [TryOpenConnection] Local Process ID is 9192
LogStaticLightingSystem: Running Lightmass w/ ImmediateImport mode ENABLED
LogStaticLightingSystem: Running Lightmass w/ ImmediateProcess mode ENABLED
LogStaticLightingSystem: Running Lightmass w/ Sorting mode ENABLED
LogStaticLightingSystem: Running Lightmass w/ Mapping paddings ENABLED
LogStaticLightingSystem: Running Lightmass w/ Mapping debug paddings DISABLED
Cmd: MAP CHECK DONTDISPLAYDIALOG
MapCheck: New page: FirstPersonExampleMap1 - 26 Aug 2016 1:17:18 am
MapCheck:Error: Error WorldInfo_0 Maps need lighting rebuilt
MapCheck: Info Map check complete: 1 Error(s), 0 Warning(s), took 133.172ms to complete.
LogEditorBuildUtils: Build time 0:05”

Any suggestions?

I’ve also tried:

  • migrating the project to a brand new project
  • deleting all the lights and rebuilding = no error, but swarm will still fail to kick off
  • restarted the engine
  • cleaned and validated the swarm cache

and everything else on this page A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums

Getting same on default VR template with one imported mesh.

I’m Not sure if this will work but try this I Had the same problem and this sorta fixed it -Open SwarmAgent.exe (Unreal Engine > [Engine Version] > Engine > Binaries > DotNET )

When you double click to open this it will place an icon in your task manager. Open that. Go to the CACHE drop down in the menu bar. Click CLEAN and then VALIDATE.

Also, Go to this folder location (may be a hidden folder on your computer so you’ll need rectify that before you can see it) C: > Users > [ Computer Name ] > AppData > Local > UnrealEngine >

Delete everything in this folder. Make sure to have the editor is closed otherwise some errors will be thrown that you cannot delete some files.

I get the same error, but nothing useful in output.log. DumpUnbuiltLightIteractions Lights with unbuilt interactions: 21Cmd: MAP CHECK NOTIFYRESULTS MapCheck: New page: - MapCheck: Error: WorldInfo_0 Maps need lighting rebuilt