[UEFN / Fortnite] Crash in all Lobby after 18 December Update

Summary

Since the Fortnite Christmas update on 18 December 2025, Fortnite and UEFN crash consistently in both Creative sessions and Battle Royale.

Please select what you are reporting on:

Unreal Editor for Fortnite

What Type of Bug are you experiencing?

Other

Steps to Reproduce

Launch Fortnite / UEFN

Open your UEFN project

Start an editing session OR enter a Battle Royale match

Wait for the lobby → crash occurs after a few seconds
(Le crash survient dans UEFN et BR, FPS chute à 0 avant le freeze / crash)

Expected Result

Fortnite / UEFN lobby should load normally without crash

Creative session should start

FPS should remain stable, allowing editing and testing of the map

Observed Result

Game freezes completely within a few seconds of lobby appearing

FPS drops suddenly to 0

No error message is displayed

Platform(s)

PC / Windows 11

GPU: NVIDIA GTX 1650

RAM: 32GB

Tested DX11/DX12

Pilots Game Ready & Studio

Additional Notes

Full reinstallation of Fortnite and UEFN done, shader caches deleted

Tested on new Windows user account → freeze still occurs

GPU tested with FurMark → stable, normal temperatures

Problem appeared after the 18 December 2025 update

Changing drivers or DX versions does not resolve the issue

Confirms issue is engine regression, not shader compilation or hardware problem