Unable to upgrade project to 4.2, crash on startup

Hi guys, having some trouble upgrading my project to 4.2. Works on 4.1, crashes on startup on 4.2. Seems to be specific to my project because others seem to work fine. Not based on ShooterGame though. Here’s the crash report:

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

Assertion failed: Class [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.2\Engine\Source\Runtime\CoreUObject\Public\UObject\Class.h] [Line: 2377]
ConstructObject called with a NULL class objec

KERNELBASE + 23544 bytes
UE4Editor_Core + 2998748 bytes
UE4Editor_Core + 1620298 bytes
UE4Editor_Core + 1561376 bytes
UE4Editor!FEngineLoop::Init() + 272 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.2\engine\source\runtime\launch\private\launchengineloop.cpp:1855]
UE4Editor_UnrealEd + 5156540 bytes
UE4Editor!GuardedMain() + 285 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.2\engine\source\runtime\launch\private\launch.cpp:124]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.2\engine\source\runtime\launch\private\windows\launchwindows.cpp:125]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.2\engine\source\runtime\launch\private\windows\launchwindows.cpp:207]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]

See attached log file.

Log file:

Hi Gigantoad -

The project that causes this issue is it a code-based and are you pulling from GitHub or was it created from the Launcher?

Thank You

Eric Ketchum

Launcher, no custom code exists only blueprints.

Hi Gigantoad -

We were able to track this error down and are currently working on a fix for it. It should be deployed as a hotfix for the Launcher soon. If you need a fix now though, the hotfix is available as a Pre-release through the GitHub version of the Engine. (4.2.1)

After the fix if this problem persists or returns please let us know.
Thank You

Eric Ketchum

Good to hear, thanks! What was the issue?

Hi Gigantoad -

It was a bug with Blueprint Asset sharing and how they are treated in the conversion process.

Eric Ketchum

I got the latest preview build from here: https://github.com/EpicGames/UnrealEngine/releases

Still crashes though. Tried with current master branch too but that one didn’t build properly. How do I get this pre-release hotfix?

Ok I found how to get this 4.21 preview build here: 4.2.1 Hotfix - Announcements - Epic Developer Community Forums

So I’m now on 4.21 and if that’s the correct build then I’m afraid I’m still having the same issue. See attached log file.

Ok I found how to get this 4.21 preview build here: 4.2.1 Hotfix - Announcements - Epic Developer Community Forums

So I’m now on 4.21 and if that’s the correct build then I’m afraid I’m still having the same issue. See attached log file.

Hi Gigantoad -

The fix for this issue has not been pushed to the public yet, it currently is in testing to ensure that it works and doesn’t break anything else.

Thanks and I will keep you informed but I have no time table just yet -

Eric Ketchum

Oh I see, thanks. What was this all about then :smiley:

“If you need a fix now though, the hotfix is available as a Pre-release through the GitHub version of the Engine. (4.2.1)”

So I’ll keep using 4.1 unitl I hear more.