Crash on load HTML5 (works on iOS) ExportMap.IsValidIndex( Index.ToExport() )) failed

Just trying to get my project running on HTML5, UE 4.9.2, but receiving this error:

Expression (ExportMap.IsValidIndex(Index.ToExport() )) failed in D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.9\Engine\Source\Runtime\CoreUObject\Private\UObject\LinkerLoad.cpp:3970! Check console for details.

  • There is just one map, barely anything in it, and it loads and plays fine on iPad 3, iPhone 6S Plus, and in PIE, PC.
  • Tappy Chicken runs OK.
  • If I run the “Entry” map, that loads fine.
  • If I modify “Entry” to use my game mode, it crashes.
  • Project is blueprint only
  • Have tried Firefox, Chrome, and FF Nightly
  • I have added the map to the “list of maps to include in a packaged build”, and have checked “full rebuild” just in case.

Is anyone able to tell, from the attached log / stack trace what might be going wrong? The log is taken from firefox.

Found the cause - “select” nodes in blueprint. Using a switch or the specific “select int”, “select color” nodes instead of the generic “Select” node seems to stop the crash. Made a proper bug for that here.

Just confirming, after replacing ~30 select nodes from my project and shared function libraries, the project now runs on html5 fine. For now I’m using the more specific typed “select” nodes (select int, select vector, etc), or local variables/branching as a replacement. Not ideal but yay for being able to send people an HTML5 link to test early builds :slight_smile:

Sorry, but do you know if any progress has been made on this bug?