UMG Widget crashes on compile

Development Programming & Scripting UI
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1

I’ve created a UMG Widget, and the Editor crashes every time I click to Compile it. I believe it is the same error each time.

Here is the callstack from the Crash Reproter:

Access violation - code c0000005 (first/second chance not available)

UE4Editor_UMGEditor + 1295505 bytes
UE4Editor_UMGEditor + 1469887 bytes
UE4Editor_UMGEditor + 1063486 bytes
UE4Editor_UMGEditor + 780609 bytes
UE4Editor_UMGEditor + 1542044 bytes
UE4Editor_UMGEditor + 1380179 bytes
UE4Editor_Kismet + 992204 bytes
UE4Editor_Kismet + 1007276 bytes
UE4Editor_Engine + 600292 bytes
UE4Editor_UnrealEd + 9881830 bytes
UE4Editor_Kismet + 727159 bytes
UE4Editor_Kismet + 992849 bytes
UE4Editor_Kismet + 1007926 bytes
UE4Editor_Slate + 588774 bytes
UE4Editor_Slate + 1535133 bytes
UE4Editor_Slate + 1030727 bytes
UE4Editor_Slate + 1037049 bytes
UE4Editor_Slate + 1435577 bytes
UE4Editor_Slate + 2116506 bytes
UE4Editor_Slate + 2296435 bytes
UE4Editor_Slate + 432060 bytes
UE4Editor_Slate + 160583 bytes
UE4Editor_Slate + 832224 bytes
UE4Editor_Slate + 770598 bytes
UE4Editor_Core + 2484713 bytes
UE4Editor_Core + 2400763 bytes
UE4Editor_Core + 2489275 bytes
UE4Editor_Core + 2387186 bytes
user32 + 9268 bytes
user32 + 8855 bytes
UE4Editor_Core + 2490486 bytes
UE4Editor!FEngineLoop::Tick() + 3434 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\launchengineloop.cpp:2193]
UE4Editor!GuardedMain() + 479 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\launch.cpp:131]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]

2

Any solutions to this problem? I keeps happening on 4.6.1 when selecting UMG widget elements and compiling.
Project runs fine after restarting, though.

3

I have not tried. I can confirm it was present in 4.5.

Reproduction of this issue in a new project / blueprint is difficult. This never happens in newly created widgets. The widgets that develop this behaviour can be very simple, though - I got to a point where a Sizebox and an Image (no variables or references) would crash 100%.

The worst/best part is that the project still runs fine, but one can no longer edit the widget. The widget’s Graph can be compiled, but compiling the Designer after selecting any of its elements (the widget does not even gets flagged as dirty) results in the error mentioned by the OP.

Also, a new widget recreated from scratch with the same elements may or may not crash. Seems pretty random.

Waiting for 4.7 (or feedback on this crash) rather impatiently. :expressionless:

4

Could you reproduce it using a source build compiled in debug mode?

5

It’s been a seemingly random occurrence for me as well. I’ve gotten into the habit of saving my UMG widgets, and doing a Save All, before compiling a widget; just so I don’t lose any work.

I have also noticed that the crash happens when compiling after making changes in Designer mode; changes in Graph mode will compile just fine.

6

This behaviour can be somewhat mitigated by saving (as you said) and closing the Designer window if switching to the Graph helps little.

Still, this issue persists for now. I tried avoiding direct blueprint communication and any circular references. It rarely helps, though.