Put the summary of the bug you're having here

What I expected to happen was...:
Minecraft launching normally

What actually happened was...:
I got this error : 

      Minecraft has crashed!            Minecraft has crashed!            ----------------------      
Minecraft has stopped running because it encountered a problem.

— BEGIN ERROR REPORT 7cf3a456 --------Generated 13/07/20 14:52
Minecraft: Minecraft 1.2.5OS: Windows 10 (amd64) version 10.0Java: 1.8.0_51, Oracle CorporationVM: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle CorporationLWJGL: 2.9.0OpenGL: GeForce GTX 1660 Ti/PCIe/SSE2 version 4.6.0 NVIDIA 445.75, NVIDIA Corporation
java.lang.NullPointerException at java.io.Reader.<init>(Reader.java:78) at java.io.InputStreamReader.<init>(InputStreamReader.java:97) 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(Thread.java:745)--- END ERROR REPORT 71f274b5 ----------