Multiplayer Crashed on Starup

Minecraft Crash Report ----
// On the bright side, I bought you a teddy bear!

Time: 20.12.15 16:06
Description: Rendering screen

java.lang.IllegalArgumentException: bad Base64 input character at 3844: 0 (decimal)
at io.netty.handler.codec.base64.Base64.decode(Base64.java:247)
at io.netty.handler.codec.base64.Base64.decode(Base64.java:197)
at io.netty.handler.codec.base64.Base64.decode(Base64.java:188)
at azk.c(SourceFile:212)
at azk.a(SourceFile:145)
at awd.a(SourceFile:25)
at awi.b(SourceFile:412)
at awi.a(SourceFile:211)
at azh.a(SourceFile:291)
at bfk.a(SourceFile:1039)
at ave.av(SourceFile:915)
at ave.a(SourceFile:325)
at net.minecraft.client.main.Main.main(SourceFile:124)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

– Head –
Stacktrace:
at io.netty.handler.codec.base64.Base64.decode(Base64.java:247)
at io.netty.handler.codec.base64.Base64.decode(Base64.java:197)
at io.netty.handler.codec.base64.Base64.decode(Base64.java:188)
at azk.c(SourceFile:212)
at azk.a(SourceFile:145)
at awd.a(SourceFile:25)
at awi.b(SourceFile:412)
at awi.a(SourceFile:211)
at azh.a(SourceFile:291)

– Screen render details –
Details:
Screen name: azh
Mouse location: Scaled: (293, 157). Absolute: (878, 427)
Screen size: Scaled: (534, 300). Absolute: (1600, 900). Scale factor of 3
Stacktrace:
at bfk.a(SourceFile:1039)
at ave.av(SourceFile:915)
at ave.a(SourceFile:325)
at net.minecraft.client.main.Main.main(SourceFile:124)

– System Details –
Details:
Minecraft Version: 1.8.9
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.8.0_66, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 264035152 bytes (251 MB) / 515084288 bytes (491 MB) up to 1060372480 bytes (1011 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Launched Version: 1.8.9
LWJGL: 2.9.4
OpenGL: Intel(R) HD Graphics 4000 GL version 4.0.0 - Build 10.18.10.4276, Intel
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: No
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs:
Current Language: Deutsch (Deutschland)
Profiler Position: N/A (disabled)
CPU: 4x Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz