UE 4.6.1 to 4.7 MacroLibrary crash

Development Programming & Scripting
1

Hello!

I am trying to run my 4.6.1 blueprint project in 4.7 and I get a crash as soon as I open one of the following:

  • Map
  • Blueprints (Character, Gamemode, Actor(s), i am guessing all of them)
  • MacroLibrary
  • UserWidget

I get the following crash message:

Assertion failed: Pin != nullptr [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.7\Engine\Source\Editor\BlueprintGraph\Private\K2Node_DynamicCast.cpp] [Line: 201]

Once I open a corrupted object or drag it into the level, my Editor freezes for ~6-8 seconds and then crashes. What would be a way to fix this issue / what could cause it that I can fix in my 4.6.1 blueprints before I convert it to 4.7?

Thanks a lot! :slight_smile:

Edit: Problem found in MacroLibrary! The crash occurred when Macros casted to game objects and then were converted to 4.7.

I have sucessfully restored the MacroLibrary by:

  1. Deleting all the casting from the macros in 4.6.1 (cast to player controller etc)
  2. Converting to 4.7
  3. and then reconstructing all of the functionality in 4.7
2

You are not the only one who is experiencing this issue, for some people the solution for this was to tick “Force No Precomputed Lighting” before you convert your project to 4.7 and for some others it was to remove spawning of Instances from construction scripts. For some others (like myself) there is not yet a solution.

3

Problem resolved by following a lead from this post.

Deleting the MacroLibrary worked, so I tried removing the casts from the MacroLibrary, converted and then rebuilt the logic. Worked out great, but I wonder why it would not convert but then work after being constructed in 4.7.

Any additional info regarding bad habits in Macros would be appreciated. Maybe casting in macros is a bad thing?

In any case, it should be made more obvious that the use of this can cause crashes in future versions or maybe it is a bug that can be fixed.