Describe the bug
The game crashes as soon as the menu animation (Example Animation) tries to play. The crash seems to happen when OptiFine Pre12 is installed, which requires OptiForge to work with Forge, which in turn requires Mixin Bootstrap to function.

To Reproduce
Steps to reproduce the behavior:

1. Launch the game
2. Install all required mods
3. Crash...

Expected behavior
No crash

Crash Report

Basic Informations (please complete the following information):

• OS: Windows 10
• FancyMenu v0.4.3
• Forge v31.1.30
• Minecraft v1.15.2
• OptiFine vHD U G1 pre12
• OptiForge v0.1.6
• Mixin Bootstrap v1.0.2

OptiForge is an unofficial mod to make the 1.15 Optifine builds compatible with Forge.
Optifine needs to add Forge support by itself. If it is still crashing in the first stable Optifine build for 1.15, I will try to fix the issue. I don’t think I can fix it now, because OptiForge seems to manipulate Forge on bytecode level to make Optifine compatible with it.

Yes, it was my fault. I've fixed it, hotfix is coming soon!
Thank you for your report!

Thanks!

FancyMenu v0.4.3.1 is now released and should hopefully fix the problem.

The previous version, v0.4.2, works just fine with Optifine & Optiforge though, so something in the newest version broke compat.