Minecraft Forums

Ok so I made this forum account as quick as possible sense i've been having errors with my minecraft, yes I know

there are other threads but they are usually dealing with different issues

or have unhelpful information.

I haven't played minecraft in a good long time sense I first bought it a few months back,

I think july or june and i recently got back into it, only issue is every time I try to get into the game

right after the loading screen on the launcher is finished it brings my right to the game output for a error that has occurred

sometimes the text of the error is small most times its this long strand of text

I've tried reinstalling it, deleting certain folders then uninstalling it then reinstalling it,

I've tried the repair button on my control panel with it, so far all the advice given to me hasn't helped at all.

At the moment im looking at one of the error screens and this is exactly as it says on the game output.

" Exception in thread "main" java.lang.NoClassDefFoundError: com/mojang/authlib/AuthenticationService
at net.minecraft.client.main.Main.main(SourceFile:39)
Caused by: java.lang.ClassNotFoundException: com.mojang.authlib.AuthenticationService
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 1 more
Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release "

Ill edit this thread if i get the larger error text to show you all what it looks like.

All help would be amazing.