Crash on Launch with Quilt Loader + Quilted Fabric API (Minecraft 1.21.5)

[justjosh104326]

Description:

Minecraft crashes immediately on launch when using the latest versions of Quilt Loader and the Quilted Fabric API. The issue has persisted across multiple updates and happens even with only one mod installed.

Steps to reproduce the behaviour:

• Launch Minecraft 1.21.5 with Quilt Loader and Quilted Fabric API (see versions below).
• Wait for the game to start.
• Observe immediate crash with exit code 1.

Expected Behaviour:

Minecraft should launch normally without crashing.

Environment:

Minecraft Version: 1.21.5

Quilt Loader Versions Tested: 0.26.4 → 0.28.1

Mod Installed: Quilted Fabric API v11.0.0-alpha.3 (only mod present)

Operating System: Windows 11 Home, version 24H2, build 26100.3624

Java Version: 1.8.0_431 (build 1.8.0_431-b10)

Crash Report:

📄 crash-2025-04-06_12.29.02.5455-quilt_loader.txt

Additional Context:

The pop-up that appears links to the Quilt User Support forum, but that site has been in "Staff Only" mode and inaccessible since late 2024. After closing the pop-up, the Minecraft Launcher reopens and shows Exit Code: 1.

[LostLuma]

As was pointed out in your last issue (#174), Quilted Fabric API is not available for the version you're trying to run it on.
In the meantime you can run use Fabric API while still using Quilt Loader on 1.21.5.