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1. Downgrading

As always, downgrading is not, was never and will never be officially supported! Please do not run 1.9 worlds in 1.8.

2. Intel Integrated GPU and random crashing

Some people with Intel integrated GPUs may see the game crashing from memory access violations. The crash log looks like this:

# A fatal error has been detected by the Java Runtime Environment: # # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00007ffb84b1172c, pid=7928, tid=9892 # # JRE version: Java(TM) SE Runtime Environment (8.0_25-b18) (build 1.8.0_25-b18) # Java VM: Java HotSpot(TM) 64-Bit Server VM (25.25-b02 mixed mode windows-amd64 compressed oops) # Problematic frame: # C [ig8icd64.dll+0x60172c] # # Failed to write core dump. Minidumps are not enabled by default on client versions of Windows # # If you would like to submit a bug report, please visit: # http://ift.tt/19dgsTD # The crash happened outside the Java Virtual Machine in native code. # See problematic frame for where to report the bug. # 

This is because of a memory leak caused by Intel's drivers. This mainly affects 6th generation Intel Core Processors (6xxx) with Intel HD Graphics 500 series, and select Intel CPUs carrying Intel HD Graphics 4400 and 4600.

To work around this issue, make sure you have the latest drivers installed and set VBO and VSync to On in the Graphics Settings. Additionally, try allocating more RAM to Minecraft.

3. OpenGL Requirements

The OpenGL requirement for 1.9 stays at OpenGL 1.3 (according to internal sources). Please report back if you have a OpenGL 1.3 only system that refuses to run Minecraft even at very low graphics settings.