Just a bug report here - applies to UE 4.6.0 and 4.6.1 on Windows:
It appears as if playing in StandAlone mode from editor can crash in a mysterious way, immediately on init, if following settings are included in /Config/DefaultEditorUserSettings.ini:
[/Script/BlueprintGraph.BlueprintEditorSettings]
bDrawMidpointArrowsInBlueprints=False
bShowGraphInstructionText=True
bUseTargetContextForNodeMenu=True
bExposeAllMemberComponentFunctions=True
bShowContextualFavorites=False
bFlattenFavoritesMenus=True
bUseLegacyMenuingSystem=False
SaveOnCompile=SoC_SuccessOnly
bJumpToNodeErrors=False
bShowActionMenuItemSignatures=False
bShowDetailedCompileResults=False
CompileEventDisplayThresholdMs=5
NodeTemplateCacheCapMB=20.000000
settings in question were probably written to config at some point in early december when I activated Save On Compile = On Success Only option in editor settings, and then Set as Default.
At any rate, with those settings in place, StandAlone mode wouldn’t work, and packaged versions of project would crash randomly on some systems, but not on others, on start-up. Removing whole section from .ini-file made problem go away.
I haven’t dug any deeper to figure out which exact option is culprit, but most likely candidate is SaveOnCompile setting.