Hello there,
I’m trying to package my project, but it’s failing and I don’t know how to fix this. 
Originally I created my project with Unreal 4.12 and then moved it to 4.15, because I wanted to use the background blur of the UMG designer. It worked without any problems. I just remember I had to reimport one sound file. I also made some minor changes to the lighting and blueprints (I added graphics settings to my pause menu). Everything worked just fine (inside the editor).
However I was also able to package my project with version 4.12.
I have two levels I’m trying to package for win64bit. The first one (UnrealForestDay) is already set as default game map.
I guess this here is the problem, but I’ll include the full log below anyway:
UE4Editor-Cmd: [2017.04.22-10.38.27:631][ 0]LogInit:Display: Warning/Error Summary (Unique only)
UE4Editor-Cmd: [2017.04.22-10.38.27:631][ 0]LogInit:Display: -----------------------------------
UE4Editor-Cmd: [2017.04.22-10.38.27:632][ 0]LogInit:Display: LogPackageName:Error: DoesPackageExist: DoesPackageExist FAILED: 'UnrealForestNight_new' is not a standard unreal filename or a long path name. Reason: Path should start with a '/'
UE4Editor-Cmd: [2017.04.22-10.38.27:632][ 0]LogInit:Display: LogPackageName:Error: DoesPackageExist: DoesPackageExist FAILED: 'UnrealForestDay' is not a standard unreal filename or a long path name. Reason: Path should start with a '/'
UE4Editor-Cmd: [2017.04.22-10.38.27:632][ 0]LogInit:Display: CookResults:Warning: Warning Unable to find package for cooking UnrealForestNight_new
UE4Editor-Cmd: [2017.04.22-10.38.27:632][ 0]LogInit:Display: LogCook:Warning: Unable to find package for cooking UnrealForestNight_new
UE4Editor-Cmd: [2017.04.22-10.38.27:632][ 0]LogInit:Display: CookResults:Warning: Warning Unable to find package for cooking UnrealForestDay
UE4Editor-Cmd: [2017.04.22-10.38.27:633][ 0]LogInit:Display: LogCook:Warning: Unable to find package for cooking UnrealForestDay
So … of course I also googled this problem. Quite some people seem to have the same or a similar problem. And I tried a couple of things, which unfortunately didn’t solve the issue:
- creating an empty project in version 4.15 and packaging it → worked
- reversing the changes I made to the widget and character blueprint
- compared the project settings with the version 4.12 → same
- went to project settings → maps & modes and set “global default server game mode” to “First Person”
- under project settings “packaging” changed the staging directory
- moved the project directory to a (way) shorter path
I also found this in the error log:
UE4Editor-Cmd: [2017.04.22-10.38.13:390][ 0]LogCook:Display: Cooking /Engine/Tutorial/Foliage/Foliage_Settings_Tutorial -> E:/Uni/CGL/5. Semester/Engine/neustes/UnrealForestProject 4.15/Saved/Cooked/WindowsNoEditor/Engine/Content/Tutorial/Foliage/Foliage_Settings_Tutorial.uasset
UE4Editor-Cmd: [2017.04.22-10.38.13:393][ 0]LogSavePackage:Display: No exports found (or all exports are editor-only) for Foliage_Settings_Tutorial. Package will not be saved.
I get this kind of error for other things too, like: LevelEditorAttract, BlueprintEditorTutorial,DummySpriteTexture, BlueprintMacroLibrariesEditorOverview, Tutorial_BP_MacroLib, LevelBlueprintEditorOverview, DestructibleMeshEditorTutorial, ParticleSystemEditorTutorial, SpriteEditorTutorial, Landscape_Painting_Mode, Landscape_Sculpt_Mode, LandscapeWalkThrough, LevelEditorOverview, PersonaAnimEditorWalkThrough, MaterialEditorTutorial, etc.
I don’t know what else I could try. I’d be really thankful for help or suggestions! Thanks in advance! 
