We recently integrated 5.5.4 from 5.5.2, and are experiencing instability both in-editor and on PCs running the editor. While callstacks like the above have surfaced, we’re also seeing BSODs affecting multiple PCs while running the editor. We didn’t have any reports of this prior to integrating 5.5.4.
While we investigate, it’d be great to know if you’ve received any similar reports from folks using 5.5.4 (or 5.5.3).
Just in case no user reports of this have come in, we’re also suspecting a recent Windows update that happened to coincide with when we did the integration. Specifically, KB5056579. We’re doing investigations to pin down if Win11 Update is the cause, in which case I’ll close this ticket 
Hi Bill,
I checked our bug DB and didn’t find anything related to UNiagaraScript or FStructuredArchiveSlot that would make sense here. Have you tried debugging to identify the UStruct or UNiagaraScript objets that part of the stack? Does the log contain anything useful? Can you share the log in case we see something you have missed?
Regarding the BSODs, this is also not something that we have heard about. What is the error code that Windows is emitting?
Martin
Thank you for confirming on your end!
I’ve locally rolled back update Microsoft KB5056579, and will continue testing. So far it’s been stable since rolling it back. Others have complained of similar issues online (general instability including BSODs) since this specific update.
When crashing in-engine, it has been overwhelmingly inside async loading, but if that update introduced a kernel bug, I could definitely see it impacting I/O or windows handles, both of which are used in that system. When it manifests, various portions of serialized objects appear corrupted, which could also point to I/O instability.
We’ve seen BSOD errors ranging from virtualized security to IRQ handlers.
If I’m stable for the rest of today, that more or less confirms it has nothing to do with 5.5.4 and everything to do with windows update.