[Crash] Visual Studio 15.5.1 and UE 4.18.1 engine build

Lately updated to Visual Studio 15.5.1 and recompiled branch 4.18.1 from github

Since new build, we get a ue4 crash when refreshing navmeshes.
It happens during startup (if map uses custom navmesh parameters - eg. cellsize) or in editor (if we ever try to change any recastnavmesh parameter).

Same project works fine with Epic 4.18.1 binary release or with our previous build with VS 15.4.5.
The problems doesn’t seem to be project related, cause crash also happens with any projects if we just try to update navmesh parameters (e.g. starter content)

Any suggestions?

ps: noticed that only some .dll and .pdb files size are slightly different from previous build (even I’m using exactly the same source code), but this is quite usual

Rolled back to 15.4.5 and recompiled ue4… no more crash.

I had no to get log of the crash, anyway repro is quite easy: just download 4.18.1 source from github, VS 15.5.1 from microsoft website and compile ue4. Then start a project, put a nav mesh bound volume on the map and change a parameter from “generation” section (e.g. tile size uu) in recast nav mesh details. UEditor will crash suddenly.

Anyone facing same problem, just follow these instructions to rollback to VS 15.4.5 and rebuild unreal engine source.
https://www.visualstudio.com/en-us/productinfo/installing-an-earlier-release-of-vs2017

I Had a same exact issue with 15.5.1 VS . Here is 2 crashlogs from 2 different projects. Log file open, 12/09/17 08:40:20LogWindows: Failed to load 'aqProf.dll' (GetLa - Pastebin.com
The second Log is from Top down Template what worked in Launcher version of engine but not in compiled source Log file open, 12/09/17 09:33:56LogWindows: Failed to load 'aqProf.dll' (GetLa - Pastebin.com

I also managed to do a rollback on VS and was able to open the project after installing 15.4.5

I had my engine crash at the exact same function a while ago, and I found out that its a compiler issue caused by the optimizations the compiler is doing. So disabling optimization for that one function did fix the issue for me:

https://puu.sh/yCRt1/8660033523.png

I have not tested this with 15.5.1, but very likely it will also fix the issue there.

Also had this issue (trying to open migrated project in 4.18.1 source build crashed consistently at 93%). Rolling back from the latest Visual Studio version to 15.4.5 worked for me!

Hey Curs0, you should not have marked your answer as the correct answer, Epic doesn’t see this bug report if you mark it as resolved.

Opened tons of blocking bugs lately, thought do not distract epic with this one…
Anyway, unmarked it

Hi Curs0,

Thank you for mentioning this issue. We have had a few reports about this crash, and have already reached out to Microsoft about this. They are looking into a fix for the compiler in Visual Studio 2017 version 15.5.

struggle this problem for 2 days, thanks very much, I’ll rollback to use 2015

the vs2017 generate wrong assembly code…

Did you try the fix that I mentioned?

Yes, it fixed, thanks very much