Summary
When launching a session, we get a “Cook Error, failed launch” message which prevents us from launching a session. No helpful logs on the cook error are provided.
Please select what you are reporting on:
Unreal Editor for Fortnite
What Type of Bug are you experiencing?
Other
Steps to Reproduce
- Launch Session
- Wait, and it fails with a cook error, where your avatar dies in the Launch Session waiting room thing
Expected Result
Successful Launch
Observed Result
Cook Error, failed launch
We hit an error while cooking this content
errors.com.epicgames.content-service.cook_failure
CookJobId:b21fc96c-6304-4f5d-a5e0-9ad247ee87f8
An error occurred while communicating with the game servers (failed to cook module 8d15ebfb-4766-7b45-9402-699db62bf15c (artifact edf6675b-a751-4d9d-82b4-1056463c3929:linux-server) (cookJobId b21fc96c-6304-4f5d-a5e0-9ad247ee87f8) with error code errors.com.epicgames.cookplugin.stagingfailure).
Command failed (Result:3): C:\build\Engine\Binaries\Win64\UnrealPak.exe “C:\build\FortniteGame\FortniteGame.uproject” -CreateDLCContainer=“C:\build\FortniteGame\Plugins\GameFeatures\8d15ebfb-4766-7b45-9402-699db62bf15c\8d15ebfb-4766-7b45-9402-699db62bf15c.uplugin” -PackageStoreManifest=“C:\temp\Temp\Cook\Cooked\LinuxServer\FortniteGame\Plugins\GameFeatures\8d15ebfb-4766-7b45-9402-699db62bf15c\Metadata\packagestore.manifest” -CookedDirectory=“C:\temp\Temp\Cook\Cooked\LinuxServer” -Commands=“C:\build\Engine\Programs\AutomationTool\Saved\Logs\IoStoreCommands.txt” -ScriptObjects=“C:\temp\Temp\Cook\Cooked\LinuxServer\FortniteGame\Plugins\GameFeatures\8d15ebfb-4766-7b45-9402-699db62bf15c\Metadata\scriptobjects.bin” -compressionformats=Oodle -compresslevel=3 -compressmethod=Mermaid -ini:Engine:[Zen]:AutoLaunch=false -ini:Engine:[Zen.ConnectExisting]:HostName=127.0.0.1 -ini:Engine:[Zen.ConnectExisting]:Port=40903 -fastexit -disableplugins=“USDStageEditor,USDImporter,ResonanceAudio,AthenaAIFunctionalTest,AutomationPawn,EditorSysConfigAssistant,EntityFrameworkTests,EditorDataStorageInternalFeatures,Spaces,Gbuffer_Turntable,CosmeticTurntable,ArtPipeEditorUtils,AnimationLibrary,DataDrivenValidationFramework,ImpostorBaker,QuestTechAutomation,BugReporter,PlasticMoonPrototypes,AudioGoldenPathExperimental,BRTests,ValkyrieTests,ValkyrieEditor,MLDeformerFramework,MLDeformer,NeuralMorphModel,NearestNeighborModel,MetaHumanCalibrationProcessing,PerforceSourceControl,TextureGraph” -ini:Game:[/Script/UnrealEd.ProjectPackagingSettings]:CustomStageCopyHandler= -cryptokeys=“C:\temp\Temp\Cook\Cooked\LinuxServer\FortniteGame\Plugins\GameFeatures\8d15ebfb-4766-7b45-9402-699db62bf15c\Metadata\Crypto.json” -compressionMinBytesSaved=1024 -compressionMinPercentSaved=5 -WriteBackMetadataToAssetRegistry=Disabled -platform=Linux -dlcName=8d15ebfb-4766-7b45-9402-699db62bf15c -csv=C:\output\alt\debug\plugin -blocksize=4KB -BasedOnReleaseVersionPath=C:\build\FortniteGame\Releases\Fortnite\Generic -unattended. See logfile for details: ‘UnrealPak-2026.03.25-03.59.10.txt’
Command failed (Result:3): C:\build\Engine\Binaries\Win64\UnrealPak.exe “C:\build\FortniteGame\FortniteGame.uproject” -CreateDLCContainer=“C:\build\FortniteGame\Plugins\GameFeatures\8d15ebfb-4766-7b45-9402-699db62bf15c\8d15ebfb-4766-7b45-9402-699db62bf15c.uplugin” -PackageStoreManifest=“C:\temp\Temp\Cook\Cooked\LinuxServer\FortniteGame\Plugins\GameFeatures\8d15ebfb-4766-7b45-9402-699db62bf15c\Metadata\packagestore.manifest” -CookedDirectory=“C:\temp\Temp\Cook\Cooked\LinuxServer” -Commands=“C:\build\Engine\Programs\AutomationTool\Saved\Logs\IoStoreCommands.txt” -ScriptObjects=“C:\temp\Temp\Cook\Cooked\LinuxServer\FortniteGame\Plugins\GameFeatures\8d15ebfb-4766-7b45-9402-699db62bf15c\Metadata\scriptobjects.bin” -compressionformats=Oodle -compresslevel=3 -compressmethod=Mermaid -ini:Engine:[Zen]:AutoLaunch=false -ini:Engine:[Zen.ConnectExisting]:HostName=127.0.0.1 -ini:Engine:[Zen.ConnectExisting]:Port=40903 -fastexit -disableplugins=“USDStageEditor,USDImporter,ResonanceAudio,AthenaAIFunctionalTest,AutomationPawn,EditorSysConfigAssistant,EntityFrameworkTests,EditorDataStorageInternalFeatures,Spaces,Gbuffer_Turntable,CosmeticTurntable,ArtPipeEditorUtils,AnimationLibrary,DataDrivenValidationFramework,ImpostorBaker,QuestTechAutomation,BugReporter,PlasticMoonPrototypes,AudioGoldenPathExperimental,BRTests,ValkyrieTests,ValkyrieEditor,MLDeformerFramework,MLDeformer,NeuralMorphModel,NearestNeighborModel,MetaHumanCalibrationProcessing,PerforceSourceControl,TextureGraph” -ini:Game:[/Script/UnrealEd.ProjectPackagingSettings]:CustomStageCopyHandler= -cryptokeys=“C:\temp\Temp\Cook\Cooked\LinuxServer\FortniteGame\Plugins\GameFeatures\8d15ebfb-4766-7b45-9402-699db62bf15c\Metadata\Crypto.json” -compressionMinBytesSaved=1024 -compressionMinPercentSaved=5 -WriteBackMetadataToAssetRegistry=Disabled -platform=Linux -dlcName=8d15ebfb-4766-7b45-9402-699db62bf15c -csv=C:\output\alt\debug\plugin -blocksize=4KB -BasedOnReleaseVersionPath=C:\build\FortniteGame\Releases\Fortnite\Generic -unattended. See logfile for details: ‘UnrealPak-2026.03.25-03.59.10.txt’
Platform(s)
PC
Upload an image
UnrealEditorFortnite.log (7.73 MB)
Additional Notes
We have not made a private build or published the map yet so I don’t have an island code I can reference. The best guess I have to provide a reference to my project is by grabbing this snippet from my .uproject file
"projectId": "e5a43bac-444b-0a6b-58f5-e685c5d904c3",
"modules":
{
"FarmTycoon": "8d15ebfb-4766-7b45-9402-699db62bf15c"
},
"bSuppressAutomaticVersePathAssignment": false,
"projectVersePath": "/aokgames@fortnite.com/FarmTycoon"
Note that I’ve been able to identify Revision 1137 as the commit that introduced something that causes a cook error. Unfortunately there’s nothing in the logs to help narrow it down, and there are 49 files that were touched on that commit making it very challenging to identify without the cook error itself.