Minecraft Forums

I did not know in which section this was put but good xD

Trying to look at Minecraft in 1.2.5 i got this:

Minecraft has crashed!
----------------------

Minecraft has stopped running because it encountered a problem.




--- BEGIN ERROR REPORT 7cf3a456 --------
Generated 31/08/17 19:16

Minecraft: Minecraft 1.2.5
OS: Windows 7 (x86) version 6.1
Java: 1.8.0_121, Oracle Corporation
VM: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
LWJGL: 2.9.0
OpenGL: ATI Mobility Radeon HD 4300 Series version 2.1.8787, ATI Technologies Inc.

java.lang.NullPointerException
at java.io.Reader.<init>(Unknown Source)
at java.io.InputStreamReader.<init>(Unknown Source)
at adn.a(SourceFile:62)
at adn.a(SourceFile:99)
at net.minecraft.client.Minecraft.a(SourceFile:262)
at net.minecraft.client.Minecraft.run(SourceFile:657)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT b359ef47 ----------

Does anyone know why it happens?

Use separate game directories for old versions of the game.