UE 4.11.2: crashes due to Unhandled Exception errors

Unreal Engine
1

Hi there! I’ve experienced a number of crashes in UE the other day. The crashes seem to have been caused by FMOD, so I’d like to ask if any of the error messages below are familiar to anyone here and how you would deal with them.

Setup: Unreal Engine 4.11.2, FMOD Studio 1.08.03, Windows 10 64bit.
Situation: In the level blueprint, three trigger volumes have an OnActorBeginOverlap node, connected to a DoOnce node which in turn triggers a Play Event 2D node.

The event to be triggered was rather plain, containing one audio track in which a multi sound module holds one WAV file (a ±3 minute piece of music). A loop region keeps the cursor on the multi sound module. No parameters were added to this event.

The idea was simple: if the player moves through any of the trigger volumes, the music starts playing. However, whenever I ran through any of the volumes in the editor, UE would crash immediately. It would freeze and Windows would prompt me to shut down UE.

Various crashes later left me with the following list of errors provided by the debugger:

Unhandled exception at 0x00007FFCFDC16516 (fmodL64.dll) in UE4Editor.exe: 0xC00000FD: Stack overflow (parameters: 0x0000000000000001, 0x000000C61B5D3FE8).

Unhandled exception at 0x00007FFCFDC16516 (fmodL64.dll) in UE4Editor.exe: 0xC0000005: Access violation writing location 0x000000C61B5D0FE8.

Unhandled exception at 0x00007FFCFF6263E4 (fmodL64.dll) in UE4Editor.exe: 0xC0000005: Access violation writing location 0x00000054ACAD0FF0.

Unhandled exception at 0x00007FFCFF8863E9 (fmodL64.dll) in UE4Editor.exe: 0xC00000FD: Stack overflow (parameters: 0x0000000000000001, 0x000000EA97483FF8).

Unhandled exception at 0x00007FFCFF8863E9 (fmodL64.dll) in UE4Editor.exe: 0xC0000005: Access violation writing location 0x000000EA97480FF8.

UE would not crash if I stopped the event from triggering by breaking the link between OnActorBeginOverlap and DoOnce (and the subsequent Play Event 2D). UE would crash if I had the event triggered by something else happening in the game. So, based on that and the error messages above, I hypothesized the FMOD event itself was somehow causing the crashes. Since I’m not at all a savvy debugger, I managed to prevent the crashes from happening only by making a new event with the same functionality and having that new event trigger from the OnActorBeginOverlap events. So I’ve changed nothing in Unreal except for the event that’s to be played by the Play Event 2D node. That seemed to work: there have been no more crashes ever since.

I’ve been very satisfied with FMOD Studio ever since I started using it well over a year ago, and I’ve never had this happen before. Do the error messages mean anything that can help understand why the event seemed to crash UE?

I’ll be glad to provide any additional information.

Thanks!

2

From what you have said, it sounds like there is something in particular with that event that causes a crash when triggered. If you run FMOD Studio validate, does it find any errors in your project?

To help track it down, could you create a new empty blueprint project, copy your banks into that project, and trigger the event there and see if it crashes? If so, that would be a simple repro that you can send to support@fmod.com with banks and we can investigate at our end.

3

Hi Geoff, thanks for getting back so quickly.

FMOD Studio validate does not find any errors in the project. This weekend I’m going to create a new empty blueprint project, copy the banks into there and trigger the event to see if it crashes. I’ll post the outcome here.

4

Much to my embarrassment, I can’t get the new, empty blueprint project to import the FMOD banks. I’ve unzipped fmodstudio10803ue4.11win64 to Epic Games’ 4.11 folder (and, alternatively, the test project’s Plugins folder). The plugin shows up in the Unreal editor, project settings and the help menu, confirming that it’s the plugin for FMOD 1.08.03. In FMOD Studio 1.08.03, I made a copy of the original project and deleted all events and audio files except for those related to the event causing the crash and its replacement event.

Unfortunately, after building in FMOD to the UE project’s Content\FMOD folder, only the banks’ folder structure is shown (i.e. Mobile, Desktop). The folders themselves appear empty in UE’s content browser, although the .bank files are present in the folders, as can be seen in Windows Explorer.

Manually dragging the banks into the content browser returns an error (.bank - unknown file extension). Running ‘Validate FMOD’ in Unreal’s Help menu tells me that the plugin ‘Failed to load banks’, followed by ‘Finished validation. Problems were detected’, but no further information. This also happened some time ago when I mismatched the FMOD plugin with a wrong version of Unreal Engine, but that can hardly be the case here.

As far as I know, I’ve integrated the FMOD plugin correctly into Unreal Engine, following every step on http://www.fmod.org/documentation/#content/generated/engine_ue4/getting_started.html just to be sure, up until ‘Compiling the plugin (optional)’. Any idea how to solve this?

5

Are there any warnings or errors in the output log? If it is failing to load bank files then it should print some sort of message. That might tell us what is going on.

6

Certainly! The output log shows the following error and warning when I load the UE project or reload the FMOD banks from UE’s File menu:

“LogFMOD: Loading strings bank: D:/Mijn documenten/Unreal Projects/SvZantenCrashTest/Content/FMOD/Desktop/Master Bank.strings.bank

LogFMOD:Error: c:\jk\workspace\Build__1.8__UE4Libs_Win\studio_api\src\fmod_bankmodel.cpp(343) – Failed to open file ‘D:/Mijn documenten/Unreal Projects/SvZantenCrashTest/Content/FMOD/Desktop/Master Bank.strings.bank’

LogFMOD:Warning: Failed to load strings bank: D:/Mijn documenten/Unreal Projects/SvZantenCrashTest/Content/FMOD/Desktop/Master Bank.strings.bank”.

7

Can you build your banks from Studio and check the file time has changed? If it still happens after building again, you can contact support@fmod.com and send us the bank. We can see if there are any problems with it.

8

Yep, the file time changes after rebuilding the banks from Studio. I’ll send the banks over to support@fmod.com. In the meantime, thanks for your help!