# Assertion failed on debug builds

**URL:** <https://qa.fmod.com/t/assertion-failed-on-debug-builds/11760>\
**Category:** Unreal Engine\
**Created:** [December 9, 2014, 8:40pm UTC](https://qa.fmod.com/t/assertion-failed-on-debug-builds/11760 "2014-12-09T20:40:36Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Torque](https://avatars.discourse-cdn.com/v4/letter/t/da6949/32.png) [@Torque](https://qa.fmod.com/u/Torque)\
**Post date:** [December 9, 2014, 8:40pm UTC](https://qa.fmod.com/t/assertion-failed-on-debug-builds/11760/1 "2014-12-09T20:40:36Z")

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I’m trying to run a **debug** build of UE4 Editor on Win64 but whenever we click Play in editor we get assertion errors. There are no problems with development builds but debug specifically is unusable. We have tried WindowsNoEditor standalone and Editor builds (in debug configuration) and all fail with the same error:

Assertion failed!  
Program: …ries\ThirdParty\FMODStudio\Win64\fmodstudioD64.dll  
File: c:\jk\workspace\Build\_1.5\_UE4Libs\_…\fmod\_factory.cpp  
Line: 184

Expression: 0

We are using version 4.5 UE4 and Fmod Version 1.05.08 Disabling FMOD fixes the problem (as you’d expect)

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**Author:** ![geoff](https://avatars.discourse-cdn.com/v4/letter/g/a3d4f5/32.png) [@geoff](https://qa.fmod.com/u/geoff)\
**Post date:** [December 12, 2014, 12:42am UTC](https://qa.fmod.com/t/assertion-failed-on-debug-builds/11760/2 "2014-12-12T00:42:30Z")

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That assert indicates there are multiple copies of one of the global bus objects in the bank, which shouldn’t normally happen. We’ll need a copy of the bank files to see what is going on in your case.

If you email [support@fmod.com](mailto:support@fmod.com) we can follow up from there.