Build failing in UE5 after switching from convai 4.0.0 to 3.9.6 for pixel streaming

[Debashruto_Bhattacha]

As the title suggests I had setup convai 4.0.0 but I required pixel streaming so I had to switch to 3.9.6. But now I am getting the error below

UATHelper: Packaging (Windows): LogWindows: Error: appError called: Can’t save ‘E:/Build/AVE_Sunil_01/Saved/Cooked/Windows/ArchVizExplorer/Plugins/Convai/Content/Core/ConvaiBaseCharacter.uasset’: Illegal reference to private object: ‘BP_POI_C /Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel.BP_POI_Amenitiy_Pool_1’ referenced by ‘Unknown referencer’ (at ‘Unknown owner’) in its ‘Unknown property’ property (private object belongs to an external map).
UATHelper: Packaging (Windows): LogWindows: Error: begin: stack for UAT
UATHelper: Packaging (Windows): LogWindows: Error: === Critical error: ===
UATHelper: Packaging (Windows): LogWindows: Error:
UATHelper: Packaging (Windows): LogWindows: Error: Can’t save ‘E:/Build/AVE_Sunil_01/Saved/Cooked/Windows/ArchVizExplorer/Plugins/Convai/Content/Core/ConvaiBaseCharacter.uasset’: Illegal reference to private object: ‘BP_POI_C /Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel.BP_POI_Amenitiy_Pool_1’ referenced by ‘Unknown referencer’ (at ‘Unknown owner’) in its ‘Unknown property’ property (private object belongs to an external map).
UATHelper: Packaging (Windows): LogWindows: Error:
UATHelper: Packaging (Windows): LogWindows: Error:
UATHelper: Packaging (Windows): LogWindows: Error: end: stack for UAT
PackagingResults: Error: appError called: Can’t save ‘E:/Build/AVE_Sunil_01/Saved/Cooked/Windows/ArchVizExplorer/Plugins/Convai/Content/Core/ConvaiBaseCharacter.uasset’: Illegal reference to private object: ‘BP_POI_C /Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel.BP_POI_Amenitiy_Pool_1’ referenced by ‘Unknown referencer’ (at ‘Unknown owner’) in its ‘Unknown property’ property (private object belongs to an external map).
PackagingResults: Error: begin: stack for UAT
PackagingResults: Error: === Critical error: ===
PackagingResults: Error: Can’t save ‘E:/Build/AVE_Sunil_01/Saved/Cooked/Windows/ArchVizExplorer/Plugins/Convai/Content/Core/ConvaiBaseCharacter.uasset’: Illegal reference to private object: ‘BP_POI_C /Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel.BP_POI_Amenitiy_Pool_1’ referenced by ‘Unknown referencer’ (at ‘Unknown owner’) in its ‘Unknown property’ property (private object belongs to an external map).
PackagingResults: Error: end: stack for UAT
UATHelper: Packaging (Windows): Took 1,278.02s to run UnrealEditor-Cmd.exe, ExitCode=3
UATHelper: Packaging (Windows): Cook failed.
UATHelper: Packaging (Windows): (see C:\Users\User\AppData\Roaming\Unreal Engine\AutomationTool\Logs\D+UE_5.5\Log.txt for full exception trace)
UATHelper: Packaging (Windows): AutomationTool executed for 0h 21m 25s
UATHelper: Packaging (Windows): AutomationTool exiting with ExitCode=25 (Error_UnknownCookFailure)
UATHelper: Packaging (Windows): BUILD FAILED
LogStreaming: Display: FlushAsyncLoading(397): 1 QueuedPackages, 0 AsyncPackages
PackagingResults: Error: Unknown Cook Failure

”BP_POI_Amenitiy_Pool_1” is an object I’ve added for scene perception. And it’s causing an issue with the build process. I followed this video: https://youtu.be/jqNttRE3nD4?si=vWu6OT3w6jhH78ux . Could anyone help me identify what the issue is?

[Debashruto_Bhattacha]

I removed all the objects I had added to scene perception and I am still getting the error below

UATHelper: Packaging (Windows): LogWindows: Error: appError called: Can’t save ‘E:/Build/AVE_Sunil_01/Saved/Cooked/Windows/ArchVizExplorer/Plugins/Convai/Content/Core/ConvaiBaseCharacter.uasset’: Illegal reference to private object: ‘BP_Explorer_Pawn_C /Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel.BP_Explorer_Pawn_2’ referenced by ‘BP_Pia_C_0’ (at ‘/Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel’) in its ‘CallFunc_GetOwner_ReturnValue_1’ property (private object belongs to an external map). UATHelper: Packaging (Windows): LogWindows: Error: begin: stack for UAT UATHelper: Packaging (Windows): LogWindows: Error: === Critical error: === UATHelper: Packaging (Windows): LogWindows: Error: UATHelper: Packaging (Windows): LogWindows: Error: Can’t save ‘E:/Build/AVE_Sunil_01/Saved/Cooked/Windows/ArchVizExplorer/Plugins/Convai/Content/Core/ConvaiBaseCharacter.uasset’: Illegal reference to private object: ‘BP_Explorer_Pawn_C /Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel.BP_Explorer_Pawn_2’ referenced by ‘BP_Pia_C_0’ (at ‘/Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel’) in its ‘CallFunc_GetOwner_ReturnValue_1’ property (private object belongs to an external map). UATHelper: Packaging (Windows): LogWindows: Error: UATHelper: Packaging (Windows): LogWindows: Error: UATHelper: Packaging (Windows): LogWindows: Error: end: stack for UAT PackagingResults: Error: appError called: Can’t save ‘E:/Build/AVE_Sunil_01/Saved/Cooked/Windows/ArchVizExplorer/Plugins/Convai/Content/Core/ConvaiBaseCharacter.uasset’: Illegal reference to private object: ‘BP_Explorer_Pawn_C /Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel.BP_Explorer_Pawn_2’ referenced by ‘BP_Pia_C_0’ (at ‘/Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel’) in its ‘CallFunc_GetOwner_ReturnValue_1’ property (private object belongs to an external map). PackagingResults: Error: begin: stack for UAT PackagingResults: Error: === Critical error: === PackagingResults: Error: Can’t save ‘E:/Build/AVE_Sunil_01/Saved/Cooked/Windows/ArchVizExplorer/Plugins/Convai/Content/Core/ConvaiBaseCharacter.uasset’: Illegal reference to private object: ‘BP_Explorer_Pawn_C /Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel.BP_Explorer_Pawn_2’ referenced by ‘BP_Pia_C_0’ (at ‘/Game/01-PROJECTS/01-SAMPLE-EXTERIOR/01-LEVELS/Z-SLV-EXPLORER.Z-SLV-EXPLORER:PersistentLevel’) in its ‘CallFunc_GetOwner_ReturnValue_1’ property (private object belongs to an external map). PackagingResults: Error: end: stack for UAT UATHelper: Packaging (Windows): Took 1,505.00s to run UnrealEditor-Cmd.exe, ExitCode=3 UATHelper: Packaging (Windows): Cook failed. UATHelper: Packaging (Windows): (see C:\Users\User\AppData\Roaming\Unreal Engine\AutomationTool\Logs\D+UE_5.5\Log.txt for full exception trace) UATHelper: Packaging (Windows): AutomationTool executed for 0h 25m 13s UATHelper: Packaging (Windows): AutomationTool exiting with ExitCode=25 (Error_UnknownCookFailure) UATHelper: Packaging (Windows): BUILD FAILED LogStreaming: Display: FlushAsyncLoading(397): 1 QueuedPackages, 0 AsyncPackages PackagingResults: Error: Unknown Cook Failure

[K3]

Hello,

Could you please share the full build logs so we can see the exact errors? Also, is this a brand new project or an existing one where you downgraded from 4.0.0 to 3.9.6?

There are major differences between 4.0.0 and 3.9.6, so please do not overwrite the plugin. Remove Convai completely from the project, then add the 3.9.6 plugin from scratch and rebuild.

[Anmol]

Apply These Steps to Fix the Unreal Cook/Packaging Error :

1. Open BP_Pia blueprint → Compile and Save it.

2. In BP_Pia → Class Defaults, clear any reference pointing to BP_Explorer_Pawn or any actor from the Z-SLV-EXPLORER level.

3. Check BP_Pia variables and make sure any Actor / Pawn / Character reference has its default value set to None.

4. Open level Z-SLV-EXPLORER, select BP_Pia_C_0, and click Reset to Default on any overridden properties (yellow arrows).

5. Ensure the pawn reference is set at runtime (BeginPlay → Get Player Pawn) instead of being stored in blueprint defaults.

6. Close Unreal and delete the Saved and Intermediate folders from the project directory.

7. Reopen the project, Compile All Blueprints, and run Package Project again.