I have a repeatable process where I will:
- open my project
- open a blueprint where the parent is one of my C++ classes (any of them)
- add a node setting a variable inherited from the C++ parent (even if it’s not connected to any other node or exec)
- press save.
this causes the editor to crash with the error
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000050 (always that address if it makes a difference)
I’ve tried cleaning the solution, rebuilding, deleting the intermediate and binaries. I don’t know anymore.
the weirdest part to me is that the game does still run without errors as long as I don’t touch anything C++ related.
Hey there @GabionSquared! Welcome back to the community! If possible, could you attach the VS debugger and see what the entire callstack is? It might provide a bit more insight into which part is failing.
Hi there - i opened unreal editor from visual studio in Development Editor mode
the part where i open the blueprint and save in the Log reads
[2025.05.25-07.27.03:359][892]LogAssetEditorSubsystem: Opening Asset editor for Blueprint /Game/Blueprints/BP_UnitController.BP_UnitController
[2025.05.25-07.27.03:361][892]LogChaosDD: Not creating Chaos Debug Draw Scene for world World_6
[2025.05.25-07.27.03:610][892]LogAssetEditorSubsystem: Opening Asset editor for Blueprint /Game/Blueprints/BP_DiceManager.BP_DiceManager
[2025.05.25-07.27.03:610][892]LogChaosDD: Not creating Chaos Debug Draw Scene for world World_7
[2025.05.25-07.27.04:296][892]LogClass: Warning: Member ‘Enum’ of EnumProperty /Game/Blueprints/Data/Struct_UnitData.Struct_UnitData:Faction_52_476689274FE38F56DBD3EBAFB1CB86CD is nullptr, export operation would fail. This can occur when the enum class has been moved or deleted.
[2025.05.25-07.27.04:296][892]LogClass: Warning: Member ‘Enum’ of EnumProperty /Game/Blueprints/Data/Struct_UnitData.Struct_UnitData:Faction_52_476689274FE38F56DBD3EBAFB1CB86CD is nullptr, export operation would fail. This can occur when the enum class has been moved or deleted.
[2025.05.25-07.27.04:350][892]LogSlate: Took 0.033760 seconds to synchronously load lazily loaded font ‘../../../Engine/Content/Slate/Fonts/Roboto-BoldCondensed.ttf’ (158K)
[2025.05.25-07.27.13:892][401]LogClass: Warning: Member ‘Enum’ of EnumProperty /Game/Blueprints/Data/Struct_UnitData.Struct_UnitData:Faction_52_476689274FE38F56DBD3EBAFB1CB86CD is nullptr, export operation would fail. This can occur when the enum class has been moved or deleted.
[2025.05.25-07.27.26:732][102]LogFileHelpers: InternalPromptForCheckoutAndSave started…
[2025.05.25-07.27.26:835][102]OBJ SavePackage: Generating thumbnails for [0] asset(s) in package [/Game/Blueprints/BP_UnitController] ([2] browsable assets)…
[2025.05.25-07.27.26:840][102]OBJ SavePackage: Finished generating thumbnails for package [/Game/Blueprints/BP_UnitController]
[2025.05.25-07.27.26:840][102]Cmd: OBJ SAVEPACKAGE PACKAGE=“/Game/Blueprints/BP_UnitController” FILE=“../../../../Unreal Projects/Warhammer/Content/Blueprints/BP_UnitController.uasset” SILENT=true
Exception thrown at 0x00007FFE13C943B5 (UnrealEditor-CoreUObject.dll) in UnrealEditor.exe: 0xC0000005: Access violation reading location 0x0000000000000050.
i noted it talks about “Member ‘Enum’ of EnumProperty in Struct_UnitData is nullptr” so i checked that asset, and the Faction enum had defaulted to Byte rather than the C++ enum. I changed that and tried again, with the error now just being:
[2025.05.25-07.39.08:724][ 17]LogFileHelpers: InternalPromptForCheckoutAndSave started…
[2025.05.25-07.39.08:778][ 17]OBJ SavePackage: Generating thumbnails for [0] asset(s) in package [/Game/Blueprints/BP_UnitController] ([2] browsable assets)…
[2025.05.25-07.39.08:779][ 17]OBJ SavePackage: Finished generating thumbnails for package [/Game/Blueprints/BP_UnitController]
[2025.05.25-07.39.08:779][ 17]Cmd: OBJ SAVEPACKAGE PACKAGE=“/Game/Blueprints/BP_UnitController” FILE=“../../../../Unreal Projects/Warhammer/Content/Blueprints/BP_UnitController.uasset” SILENT=true
Exception thrown at 0x00007FFE031C43B5 (UnrealEditor-CoreUObject.dll) in UnrealEditor.exe: 0xC0000005: Access violation reading location 0x0000000000000050.
any thoughts?
Excellent find, that looks like it only solved a symptom of the issue and not the full issue. There seems to be something wrong with either the enum’s definition (wherever it was defined) or the BP_UnitController itself. It’s possible that there’s some corrupt data.
If you can (safely) remove the enum from it, then try to save, that may give us a better clue.
that seems to have fixed it?
the file the enum was in just contained a few other enums and a dataasset class which could all be deleted fairly safely, then i deleted the cpp and .h files following this post
when i relaunched, the crashing error had stopped. I guess that file had just been corrupted at some point?
I’ve rewritten the deleted file more-or-less exactly how it was and it’s working perfectly
thanks for the help!
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Great job! Sometimes the files (or cached data for those files) can be corrupted in some way. Often enough, (like you tried originally) wiping the caching folders corrects this, but sometimes the only thing you can do is run the debugger, finding the offending asset, then try to correct it if possible at best or replace it at worst. Data types like structs and enums can end up having this issue in larger projects. This is where I always recommend to every user to have some form of source control (Git, Perforce, etc) and use it frequently. Even when working on a project alone, the benefits of source control are innumerable!