Weird Material Bug / Crash

I’m very new to UE4. (only got It 2 days ago)
Whilst using UE4 (4.7 preview version), I set some materials on my bsps to Planar. After doing this, it suddenly stretches and if I try and undo it crashes.
Is this a bug specific to 4.7?
Its quite frustrating and I’ve lost a lot of progress.

For some reason I’ve tried posting a new thread and It has failed to upload many times. I am also unable to upload attachments due to some database issue
This is a screenshot of the problem in-editor.

This is the crash screen and its contents:

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

Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.7\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 679]
Array index out of bounds: 154 from an array of size 149

KERNELBASE + 24684 bytes
UE4Editor_Core + 3139204 bytes
UE4Editor_Core + 1613752 bytes
UE4Editor_Core + 1494146 bytes
UE4Editor_Engine + 5418995 bytes
UE4Editor_Engine + 5707183 bytes
UE4Editor_Engine + 4950068 bytes
UE4Editor_Engine + 9839441 bytes
UE4Editor_UnrealEd + 1840904 bytes
UE4Editor_UnrealEd + 6722646 bytes
UE4Editor!FEngineLoop::Tick() + 4084 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launchengineloop.cpp:2240]
UE4Editor!GuardedMain() + 479 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launch.cpp:131]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]

Welcome! :smiley:

Hmm, in my case it works as it should -> which material do you use? (a custom one or one from the starter content) Also make sure to post the log files which gets created after the crash -> Project-Saved-Logs + post your problem onto answerhub:

My first advice would be to start a project with a complete and stable build like 4.6.1. The 4.7 preview is still “under construction” and does not have all the kinks worked out yet. However, if you would like to help identify some of the problems so they be addressed (like the one you’re experiencing) you should post this on the AnswerHub following these guidelines:

Ok. Thanks for the advice! :slight_smile: