I have the problem that when I join the server, my Minecraft sometimes crashes.
Even if I join one of my worlds. Have the problem only recently, and did not have it before.

If I click on "Show Crash Report" nothing happens, and I will not see it either, only if I go to "More Information" : 
The game crashed whilst unexpected error
Error: java.lang.NullPointerException: Unexpected error


It's there everytime

 Ok, thanks