My game crashed when i tryed to open a toolbox that contained a Forestry Backpack (It was ok when i insert it on the toolbox).
It may have to do with the backpack Heavy use of NBT Tags or something. Also i dunno if it would happen in 1.9.0 if someone is nice enough to test it thanks.
Edit: Luckly the items inside didnt vanish and my game loaded normally, give me a second and ill provide an error log.
Display Spoiler
Mods loaded: 34
ModLoader 1.2.3
mod_MinecraftForge 1.4.1.59
mod_ModLoaderMp 1.2.3v3
mod_NotEnoughItems 1.2.0
mod_ReiMinimap v3.0_03 [1.2.3]
mod_SmartMoving 7.2
mod_AS_BattleTowers 1.2.3
mod_BuildCraftBuilders 3.1.4
mod_BuildCraftCore 3.1.4
mod_BuildCraftEnergy 3.1.4
mod_BuildCraftFactory 3.1.4
mod_BuildCraftSilicon 3.1.4
mod_BuildCraftTransport 3.1.4
mod_SneakyPipes 0.1.0 (Minecraft 1.2.3, Buildcraft 3.1.4, Forge 1.4.0.52)
mod_CraftGuide 1.4.3 for Minecraft 1.2.3
mod_EnderChest 1.0.2
mod_Forestry 1.4.0.4
mod_BuildCraftZFP (Forestry Package)
mod_IC2 v1.81
mod_BCIC2Crossover IBv0.07 for MC 1.2.3, BC 3.1.4, IC2 1.81
mod_IC2AdvancedMachines v3.8
mod_MagicYarn 1.1
Compact Solar (2.0) rev 0 build 0 2.0
mod_IronChest 3.1
mod_QuickGuide 1.2.3
mod_RedPowerArray 2.0pr4e
mod_RedPowerCore 2.0pr4e
mod_RedPowerLighting 2.0pr4e
mod_RedPowerLogic 2.0pr4e
mod_RedPowerMachine 2.0pr4e
mod_RedPowerWiring 2.0pr4e
mod_RedPowerWorld 2.0pr4e
mod_TurretMod 1.2.3 v.2.0
mod_ThaumCraft 2.0
Minecraft has crashed!
----------------------
Minecraft has stopped running because it encountered a problem.
--- BEGIN ERROR REPORT d91ad993 --------
Generated 02/04/12 09:51 PM
Minecraft: Minecraft 1.2.3
OS: Windows 7 (amd64) version 6.1
Java: 1.6.0_27, Sun Microsystems Inc.
VM: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Sun Microsystems Inc.
LWJGL: 2.4.2
OpenGL: GeForce GT 220/PCIe/SSE2 version 3.3.0, NVIDIA Corporation
java.lang.ArrayIndexOutOfBoundsException: 8
at ic2.common.ItemToolbox.unpack(ItemToolbox.java:151)
at ic2.common.ItemToolbox.a(ItemToolbox.java:81)
at aai.a(SourceFile:98)
at kf.a(PlayerController.java:77)
at net.minecraft.client.Minecraft.c(Minecraft.java:1401)
at net.minecraft.client.Minecraft.k(Minecraft.java:1811)
at net.minecraft.client.Minecraft.x(Minecraft.java:842)
at net.minecraft.client.Minecraft.run(Minecraft.java:747)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT e3cc10f0 ----------
Edit2: It may have to do more with having a full QuickSlot bar rather than a backpack thingy.