Cannot open widget blueprint - Unhandled Exception: EXCEPTION_STACK_OVERFLOW

Development Programming & Scripting UI
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1

I’ve been working on refactoring some UI elemenets in my project, using UE5.1.1, and everything seemed to be working fine (with only the usual number of crashes) until I noticed that one particular Widget Blueprint was causing a crash every time I interacted with it - even right clicking it in the content browser. After testing some others, the same thing occurs with some (but not all) of my widgets, most of which are inheriting from the same class and have the same minimal logic in them.

I can’t figure out why this would be happening to some but not all, and the fact that I can’t even interact with them to delete & refactor the references in the editor them is going to make this a huge PIA. Even if I delete the corrupt widget (from file explorer) it also looks like any other widget that referenced it still breaks.

Would appreciate any ideas what might be causing this and how to best go about fixing it.

The crash:

Unhandled Exception: EXCEPTION_STACK_OVERFLOW

UnrealEditor_UnrealEd
UnrealEditor_UnrealEd
UnrealEditor_UMG
UnrealEditor_UMG
UnrealEditor_UMG
UnrealEditor_UMG
UnrealEditor_UMG
etc

And what I can easily get out of the .dmp file:

PROCESS_NAME:  UnrealEditor.exe

RECURRING_STACK: From frames 0x1 to 0x3

ERROR_CODE: (NTSTATUS) 0xc00000fd - A new guard page for the stack cannot be created.

EXCEPTION_CODE_STR:  c00000fd

EXCEPTION_PARAMETER1:  0000000000000001

EXCEPTION_PARAMETER2:  000000aed8003fe8

STACK_TEXT:  
000000ae`d8003ff0 00007ff8`f389cf68     : 00000000`00000000 00007ff9`0dc56b98 00000000`00000000 00000000`00000000 : UnrealEditor_UMG!UWidgetAnimationDelegateBinding::BindDynamicDelegates+0x81d
000000ae`d8004040 00007ff8`f393424f     : 00000000`00000000 000000ae`d80041f8 00000000`00000000 0000068b`25902100 : UnrealEditor_UMG!FUserWidgetPool::ResetPool+0x48e8
000000ae`d8004070 00007ff8`f39c25fa     : 000000ae`d80041f8 00000000`00000000 00000000`00000000 000000ae`d80041f8 : UnrealEditor_UMG!UPanelWidget::GetChildAt+0x6f
000000ae`d80040a0 00007ff8`f39c2673     : 0000068b`25902100 000000ae`d80041f8 00000000`00000000 000000ae`d80042f8 : UnrealEditor_UMG!UWidgetTree::ForWidgetAndChildren+0x1ba
000000ae`d80041a0 00007ff8`f39c2673     : 0000068b`25902400 000000ae`d80042f8 00000000`00000000 000000ae`d80043f8 : UnrealEditor_UMG!UWidgetTree::ForWidgetAndChildren+0x233
000000ae`d80042a0 00007ff8`f39c2673     : 0000068b`25902100 000000ae`d80043f8 00000000`00000000 000000ae`d80044f8 : UnrealEditor_UMG!UWidgetTree::ForWidgetAndChildren+0x233
000000ae`d80043a0 00007ff8`f39c2673     : 0000068b`25902400 000000ae`d80044f8 00000000`00000000 000000ae`d80045f8 : UnrealEditor_UMG!UWidgetTree::ForWidgetAndChildren+0x233
000000ae`d80044a0 00007ff8`f39c2673     : 0000068b`25902100 000000ae`d80045f8 00000000`00000000 000000ae`d80046f8 : UnrealEditor_UMG!UWidgetTree::ForWidgetAndChildren+0x233
000000ae`d80045a0 00007ff8`f39c2673     : 0000068b`25902400 000000ae`d80046f8 00000000`00000000 000000ae`d80047f8 : 

STACK_COMMAND:  ~0s; .ecxr ; kb

SYMBOL_NAME:  UnrealEditor_UMG+c7

MODULE_NAME: UnrealEditor_UMG

IMAGE_NAME:  UnrealEditor-UMG.dll

FAILURE_BUCKET_ID:  STACK_OVERFLOW_c00000fd_UnrealEditor-UMG.dll!Unknown

OS_VERSION:  10.0.22621.1

BUILDLAB_STR:  ni_release

OSPLATFORM_TYPE:  x64

OSNAME:  Windows 10

IMAGE_VERSION:  5.1.1.0

FAILURE_ID_HASH:  {ccac5b27-b9e8-0d47-20da-a518df2f837f}

Followup:     MachineOwner
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2

Any luck to solve this? I am on Unreal Engine 5.2 and all of a sudden locked out of widgets with this error. I can’t open or even right click on them or they crash the engine with Stack Overflow error. Some do this and some don’t.

3

Unfortunately I think I had to just delete and remake the widget, I wasn’t able to find any more information on what caused the error and it’s not like Epic respond to user bug reports.

I think the issue (in my case, anyway) was related to child widgets and named slots - it looks like the widget hierachy is very fragile and you can quickly corrupt the widget if something hops out of the hierachy somehow.