I have been using my own made 1.9.4 modpack for a while now with no problems till recently.
Mods are being updated now daily so it's hard to trace what can be causing this problem.
MultiMC Launcher 0.4.11-751 (and tried latest dev version) [also tried using official MC Launcher]
Loads fine to main menu, choose world to play and the screen just stops with 0% in the middle.
You can press escape and goes back to main menu but if try again it does the same (tested with new world as well as current made)
The error log when trying to load has a load of "Skipping event FMLModIdMappingEvent and marking errored mod ### since required dependency Forge has errored"
Reading through the forums it was suggested to look for any Unknown Recipe errors and look for updates if any. The 3 that are shown I have been using for a while now with no problems until now.
The 3 it mentioned I have tried on a fresh 1.9.4 install with just them and forge and no problems there.
I can't find what is causing the error:
[20:01:41] [server thread/ERROR] [FML]: Caught exception from Forge
java.lang.IllegalArgumentException: Comparison method violates its general contract!
If anyone can help it would be greatly appreciated.
Error log part