After upgrading to the new version of fmod studio and ue 5.6, I started getting constant crashes of the engine, which starts to strain and interfere with my work very much.
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Assertion failed: Pair != nullptr [File:D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Containers\Map.h] [Line: 729]
UnrealEditor_Core
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_FMODStudioEditor!FFMODAssetBuilder::BuildBankLookup() [D:\Games\Race_project\race_project_main\Plugins\FMODStudio\Source\FMODStudioEditor\Private\FMODAssetBuilder.cpp:359]
UnrealEditor_FMODStudioEditor!FFMODAssetBuilder::ProcessBanks() [D:\Games\Race_project\race_project_main\Plugins\FMODStudio\Source\FMODStudioEditor\Private\FMODAssetBuilder.cpp:50]
UnrealEditor_FMODStudioEditor!FFMODStudioEditorModule::ReloadBanks() [D:\Games\Race_project\race_project_main\Plugins\FMODStudio\Source\FMODStudioEditor\Private\FMODStudioEditorModule.cpp:1245]
UnrealEditor_FMODStudioEditor!FFMODStudioEditorModule::ProcessBanks() [D:\Games\Race_project\race_project_main\Plugins\FMODStudio\Source\FMODStudioEditor\Private\FMODStudioEditorModule.cpp:388]
UnrealEditor_FMODStudioEditor!TBaseRawMethodDelegateInstance<0,FFMODStudioEditorModule,void __cdecl(void),FDefaultDelegateUserPolicy>::ExecuteIfSafe() [E:\UE_5.6\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:547]
UnrealEditor_FMODStudioEditor!FFMODBankUpdateNotifier::Update() [D:\Games\Race_project\race_project_main\Plugins\FMODStudio\Source\FMODStudioEditor\Private\FMODBankUpdateNotifier.cpp:42]
UnrealEditor_FMODStudioEditor!FFMODStudioEditorModule::Tick() [D:\Games\Race_project\race_project_main\Plugins\FMODStudio\Source\FMODStudioEditor\Private\FMODStudioEditorModule.cpp:1084]
UnrealEditor_FMODStudioEditor!TBaseRawMethodDelegateInstance<0,FFMODStudioEditorModule,bool __cdecl(float),FDefaultDelegateUserPolicy>::Execute() [E:\UE_5.6\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:531]
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll
Hi,
Thank you for bringing this to our attention.
Could I get any reproduction steps that consistently cause a crash?
Hi,
Thank you for the quick response.
Here are the steps that consistently lead to a crash on my end:
1. I upgraded Unreal Engine from 5.4 to 5.6.
2. I also updated FMOD Studio to the version required by the plugin.
3. I recompiled the project — the build completed successfully without errors.
4. With both Unreal Engine and FMOD Studio open, I started working with audio as usual.
5. After making changes in FMOD Studio, I clicked the Build button to rebuild the banks.
6. Each time I do this, Unreal Engine crashes immediately after pressing Build in FMOD Studio.
7. Despite the crash, the banks are built successfully. However, the crash happens consistently every time I build.
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Thank you for the steps. I have been able to reproduce the issue. I have passed it on to our development team to investigate further.
Thanks!
Yes, I’m using release version
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My audio team is having this same issue and it has stopped work for all our other departments as well. This really needs to get escalated asap.
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Can confirm, this breaks our whole project, nobody can open the editor anymore. This needs to be fixed ASAP.
I think I’ve solved the problem for myself. After analyzing the log file after the UE crash, I found that the engine crashes on the build of only one bank. Apparently, when updating the project, one of the banks was damaged, in my case SFX.bank. I deleted this bank from the engine and rebuilt it, which solved the problem. Look in the log file for which bank your engine breaks. I hope this helps someone 
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We are working on a solution now. I will update here when there is news.
Thank you for sharing your solution.
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Would it be possible to get the call stack of this crash? I am not able to find this same line in my logs.
Thanks!
I have attached a link to the archive Google drive with all the logs that I received.
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The reason for this crash is a bug in UE 5.6.0.
See this post on EPS: UE5.6.0 - Crash in UDataTable::RemoveRow(FName RowName)
If you build your own engine, you can fix it yourself.
\Engine\Source\Runtime\Engine\Private\DataTable.cpp:
Change line 240 from
FTableRowBase* CurRow = reinterpret_cast<FTableRowBase*>(RowMap[ChangedRowName]);
to
uint8** FoundRow = RowMap.Find(ChangedRowName);
FTableRowBase* CurRow = (FoundRow ? reinterpret_cast<FTableRowBase*>(*FoundRow) : nullptr);
This avoids operator ensuring on a missing row (which it will after removing any row from a data table).
Ciao, Daniel!
EDIT: My original fix had an error, since .Find returns a pointer to a pointer… the code above has been rectified.
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Thank you for sharing the workaround! We are still working on a solution in the FMOD integration so you don’t have to compile from source.
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Do you have any kind of timeline for this patch? Are we looking at days? Or weeks? I have other departments who are still unable to open the editor even after trying to revert to previous changesets to the one that had the banks built. Needless to say, they’re really upset about this.
Thanks for this! Our team was able to build a custom engine and implement this fix on its own branch. The problem now is, the project size has increased significantly and every person on the team is forced to give up that precious hard drive space. Not the end of the world obviously, but a pain in the butt for a lot of people.
Hopefully a patch will be ready soon.
We have released a patched version with a temporary fix, while we wait for Unreal to determine a fix on their side we can investigate a more permanent solution.
2 Likes
