Summary
During UEFN playtest sessions, the Fortnite Creative client repeatedly crashes with EXCEPTION_ACCESS_VIOLATION (read and write variants seen). Every crash is preceded by a massive per-frame spam (100k-160k+ lines per session) in the log:
LogBlueprintUserMessages: Warning: Failed to find console variable ‘fort.input.upgrades.movement’.
logged roughly twice per frame, continuously, for the entire session. Immediately before each crash there is also a ~300ms game-thread hitch tied to RenderVirtualShadowMaps(Non-Nanite), followed by the fatal exception on the render/worker thread.
We confirmed this is not caused by our own project content: the string ‘fort.input.upgrades.movement’ does not appear anywhere in our project’s Verse source or in any of our project’s own Blueprint/uasset files. The spam is present across multiple separate sessions over 3 days (Sept 8-10, 2026), so it is not a regression from anything we changed - it looks like a pre-existing engine/native issue querying a console variable that no longer exists in this build.
Please select what you are reporting on:
Unreal Editor for Fortnite
What Type of Bug are you experiencing?
Stability
Steps to Reproduce
- Open a UEFN project and launch a Play-in-Fortnite / playtest session
- Check the client log (FortniteGame.log) during the session - the ‘Failed to find console variable fort.input.upgrades.movement’ warning starts appearing almost immediately and repeats continuously (roughly 2x per frame) for the whole session
- Keep the session running for an extended period (tens of minutes)
- Eventually the client crashes with EXCEPTION_ACCESS_VIOLATION, always preceded by a ~300ms hitch on RenderVirtualShadowMaps(Non-Nanite)
Expected Result
The console variable ‘fort.input.upgrades.movement’ should either exist in this build or not be queried at all - no per-frame warning spam, and no resulting client crash during normal playtest sessions.
Observed Result
The client crashes with EXCEPTION_ACCESS_VIOLATION (both read and write address variants observed) after a period of active play. The FortniteGame.log shows continuous spam of “LogBlueprintUserMessages: Warning: Failed to find console variable ‘fort.input.upgrades.movement’.” (154k-163k occurrences across sessions) starting near session start, plus a ~300ms hitch on RenderVirtualShadowMaps(Non-Nanite) immediately before each crash. Verified this is not from our own project content (no match for that string anywhere in our Verse/Blueprint assets), and it also appears in log backups from prior sessions over the last 3 days.
Platform(s)
PC (Windows) - UEFN editor Play-in-Fortnite / playtest client
Additional Notes
Confirmed the CVar string does not appear anywhere in our own project’s Verse or Blueprint content, so this looks like a native/engine-side lookup. Happy to share full log excerpts (FortniteGame.log / UnrealEditorFortnite.log) if that helps investigation.