Player safety is the top priority for us. Unfortunately, earlier today we identified a security vulnerability in Minecraft: Java Edition. The issue is patched, but please follow these steps to secure your game client and/or servers. Please RT to amplify. redsto.ne/java

Hi there, that's definitely no fun to deal with! Can you let us know what troubleshooting steps you've already tried? Uninstalling and reinstalling the launcher is usually a good first step. ^FF