We are generating a lot of blueprints from C++ (1500) and saving them is kind of painful in UE 5.5 (still not updated to 5.6). The problem is thumbnail creation, which will trigger full garbage collection from time to time. This is very slow, and I think I’ve experienced complete freeze, since I’m breaking in IncrementalDestroyGarbage(), GGCObjectsPendingDestructionCount doesn’t change for a long time. And this function was called without time limit.
One work around I can see is to not use bPerformFullPurge, another is to disable the thumbnail generation completely while saving packages.
Do you have the callstacks for where you’ve broken into just to make sure that we are looking at the same thing?
Additionally, could you take a profile capture using UnrealInsights while generating the blueprints and share the resulting trace? Our documentation for generating a profile trace can be found here. There is a uplugin called “LiveTrace” that ships with the engine which adds a small toolbar to start and stop tracing easily. The default channels for tracing should be sufficient.