Blizzard is investigating multiple reports about Diablo 4 players endlessly crashing after today's Patch 1.4.1 and has temporarily disabled the game's DLSS Frame Generation option. Just over a week ago, Blizzard disabled NVIDIA DLSS Frame Generation for all NVIDIA graphics card users due to stability issues.
Diablo 4 Patch 1.4.0a — NVIDIA DLSS Frame Generation Disabled
In a forum thread with over 30 replies, several users have found a temporary workaround by deleting their LocalPrefs.txt, which is by default located in the «Documents/Diablo IV» directory. This should reset all your settings (including graphic settings) and allow you to log in again without crashes. However, after Blizzard decided to disable DLSS Frame Generation, the workaround should no longer be necessary as it caused the crashing issue in the first place.