Ever since I upgraded to 4.9, I can no longer build lighting for any level. Even if I create a blank new map, it hangs forever at Building Lighting 50%. There is 0 cpu activity going on in task manager.
This is all that shows up in the log:
LoadErrors: New page: New Map
MapCheck: New page: Map Check
Cmd: MAP REBUILD ALLVISIBLE
LogEditorServer: Rebuildmap Clear paths rebuilt
MapCheck:Warning: Warning WorldSettings Hierarchical LOD System is disabled or no HLOD level settings available, unable to build LOD actors.
LogStats: STAT_HLOD_BuildClusters - 9.051 ms
LightingResults: New page: Lighting Build - Sep 16, 2015, 1:18:40 PM
LogStaticLightingSystem:Warning: No importance volume found, so the scene bounding box was used. You can optimize your scene’s quality and lighting build times by adding importance volumes.
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
LogEditorBuildUtils: Build time 0:00:03