Repeated Blueprint corruption. Repeated lost work

Development Programming & Scripting Blueprint
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1

Hi, my character controller blueprint keeps corrupting after maybe 6 hours of work each evening; all autosaves after this point crash the editor. It’s happened twice. It needs to stop.

The blueprint is pretty massive and complex, is there a size limit on blueprints? The recent working copy is 622kb, but the corrupt copy is only 612kb. Is there something inherently wrong with this blueprint? Can I prevent this, say, by closing and reopening the editor every 6 hours?

Most importantly, is this going to keep happening to my most vital blueprints in Unreal?

Here’s the callstack (yesterday’s crashes didn’t generate output like this, today’s crashes do):

!Id:

Unknown exception - code 00000001 (first/second chance not available)

Assertion failed: BreakpointLocation [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.4\Engine\Source\Editor\UnrealEd\Private\Kismet2\KismetDebugUtilities.cpp] [Line: 650]

KERNELBASE + 23544 bytes
UE4Editor_Core + 3095148 bytes
UE4Editor_Core + 1661722 bytes
UE4Editor_Core + 1541808 bytes
UE4Editor_UnrealEd + 9027615 bytes
UE4Editor_UnrealEd + 8767820 bytes
UE4Editor_BlueprintGraph + 1116281 bytes
UE4Editor_BlueprintGraph + 1087504 bytes
UE4Editor_BlueprintGraph + 1275032 bytes
UE4Editor_BlueprintGraph + 1279121 bytes
UE4Editor_BlueprintGraph + 569703 bytes
UE4Editor_UnrealEd + 8748579 bytes
UE4Editor_UnrealEd + 8749627 bytes
UE4Editor_CoreUObject + 608987 bytes
UE4Editor_CoreUObject + 917478 bytes
UE4Editor_CoreUObject + 1026900 bytes
UE4Editor_CoreUObject + 846788 bytes
UE4Editor_CoreUObject + 663400 bytes
UE4Editor_CoreUObject + 1065583 bytes
UE4Editor_CoreUObject + 917881 bytes
UE4Editor_CoreUObject + 1026900 bytes
UE4Editor_CoreUObject + 916062 bytes
UE4Editor_CoreUObject + 1026900 bytes
UE4Editor_CoreUObject + 916062 bytes
UE4Editor_CoreUObject + 1034610 bytes
UE4Editor_CoreUObject + 1400666 bytes
UE4Editor_CoreUObject + 1163694 bytes
UE4Editor_CoreUObject + 1160501 bytes
UE4Editor_CoreUObject + 1163994 bytes
UE4Editor_CoreUObject + 1160501 bytes
UE4Editor_CoreUObject + 1160266 bytes
UE4Editor_CoreUObject + 949472 bytes
UE4Editor_CoreUObject + 1157040 bytes
UE4Editor_CoreUObject + 922312 bytes
UE4Editor_CoreUObject + 998250 bytes
UE4Editor_CoreUObject + 1400466 bytes
UE4Editor_UnrealEd + 2593508 bytes
UE4Editor_UnrealEd + 2540781 bytes
UE4Editor_UnrealEd + 2466449 bytes
UE4Editor_UnrealEd + 5632240 bytes
UE4Editor_UnrealEd + 2959412 bytes
UE4Editor_UnrealEd + 2958584 bytes
UE4Editor_UnrealEd + 5826192 bytes
UE4Editor_UnrealEd + 5628448 bytes
UE4Editor!GuardedMain() + 285 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.4\engine\source\runtime\launch\private\launch.cpp:125]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.4\engine\source\runtime\launch\private\windows\launchwindows.cpp:125]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.4\engine\source\runtime\launch\private\windows\launchwindows.cpp:201]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]
2

Hi AdrenalineHigh,

There is no limit to the filesize of blueprints. What changes are you making to your blueprint prior to the blueprint becoming corrupted?

3

Hi AdrenalineHigh,

I’m sorry that this is happening for you. It looks like the Blueprint recorded a breakpoint that it can’t find the corresponding node for. I am unsure how you got in this state, but I could try to alleviate this crash for you. If I get a fix into GitHub, is that something that you’d be able to pull?

Hoping to help so that we can unblock you as fast as possible.

4

I made a fix that will hopefully circumvent this issue here: https://github.com/EpicGames/UnrealEngine/commit/4e7ca08c2c69b7ffcb0ca819bd1f1047ee6e91f2#diff-d41d8cd98f00b204e9800998ecf8427e

Invalid breakpoints should not block the user from opening the blueprint (we just clear the breakpoint and warn now).

That said, I don’t know how you got in this state and that is a little worrisome. I am worried that your Blueprint might have more corruption than just its breakpoints. If you’re able to take this change and try it again, let us know how that works out.

Also, if you have any more detailed repro steps that could clue us into how you got into this state that’d be great. But hopefully this works at unblocking you!

5

Blueprint corruption still a serious issue a year later. I’m stuck with a project that gets in a corrupted state if I try to modify it. This needs attention!

6

Check out this post.

I had corrupted assets when I migrated my project from 4.7.6 to 4.9.1. I managed to fix it by identifying the cause of corruption in the uasset binary and then writing a script to go through every asset and fix the corrupted bytes. While this probably isn’t the cause of your corruption, the technique I used to isolate and identify the issue may be of use to you in finding your own file corruption.

You should create your own backups of the blueprint uasset which is getting corrupted and try to replicate the corruption. If you save your blueprint once per hour to a separate folder, you can get both a backup go back solution and have enough data to start making delta comparisons between corrupted and uncorrupted blueprints. If you can find a repeatable way to corrupt a blueprint, then you can isolate and identify the cause (ie, infinite loop in construction script).