Always ask me to remove files...

Always ask me to remove files when everytime I start open minecraft.. Even I have already join realm and just want to left for a while and then join back again, this message still pop out and ask me to remove files then I need to keep quit Minecraft then jpin again.. This is annoying.. Which is everytime this will ask me to remove files and ask me to quit minecrafft then needs to join again...Please help....