Game crashing at startup in UE5.3

Hi Peeps

I’m trying to move my game over to UE5.3 as I am having an issue with 5.2 that I can’t resolve. However when I try to open the project in 5.3 it crashes with the error
Assertion failed: NumNewPins == InNewPins.Num() [File:D:\build++UE5\Sync\Engine\Source\Editor\BlueprintGraph\Private\K2Node.cpp] [Line: 1352].
If I delete the config folder I can launch the project but as soon as I try to open a level it crashes with the same message
Does anyone have any idea what this could be?
Many thanks in advance!

For our project it turned out to be an issue in our old BP. We had a BP that had a struct member (call it type FMyStruct) that at some point had been turned into a struct array member (ie. a member whose type is an array of FMyStruct). Before it had been turned into an array, someone had a Get node for it somewhere in the BP, and had split the struct pin on that node. When it had been converted into an array, that node was now had the old broken pin hanging off of it. It was trying to be a split struct pin on a member that was now an array type (which doesn’t work). Something new in UE5.3 crashes with that data set up. It looks like it finds the broken pin (which is marked to be split) and then tries to split the new node in the middle of the rewiring, which triggers an assert.

On our end we fixed this by fixing up the node in a 5.2 editor.

Hi Ian

Sorry for the very late reply, I just saw your answer when I was posting something else!
I’ll have a look in to that although I will be looking to migrate to 5.4 now.

Hi Ian

I know this is an old post but I have recently tried updating my game to 5.5 and still have the same issue. If I try to open any type of blueprint the game crashes. You mentioned that in your project it was a struct causing the issue, Do you happen to recall how you identified the offending item?

I’m pretty sure I have a similar issue but I have no idea how to find what is causing it.

Many thanks in advance

Nick