EDIT Now you just need to start up the client and Mojangs update has the patch. There's a user side fix you should implement asap! 1. Start your client, then click the 'Installations' Tab at the top 2. Click the ... and then 'edit' next to the version you are currently using. 3. Click 'more options' 4. Copy and Paste this text to the end of the text in the "JVM Arguments" box. -Dlog4j2.formatMsgNoLookups=true Do not remove anything else in there.