There was another update to fix the issue with profile parsing. It looks like some players (on Windows10?) got a forced update to 2.0.x launcher that uses a different profile format. I was not able to fully test it, as my launcher is 1.6.84j, so please check if it works for you.
Have you updated it? Current version can't produce the same message as it was removed from the code.
Can you post a screenshot/copy of the messages on the console?
Also, does anyone know where or how to download the latest launcher version 2.0.x? When I try to download the installer from minecraft.net it only downloads 1.6.84j launcher, so I can't reproduce the behavior you see.
Another question to people using 2.0 launchers - where is your profile located? Is it still at %APPDATA%/.minecraft/launcher_profiles.json or does it use some new location maybe?
Hello Dorquemada, i do have version 2.0.1003 launcher and the profile is in the same location. I had reformatted my computer and when I went to install MC this time is how I got the new version of the launcher. Hope this is useful to you. Thanks for your help and the awesome program. It would be kool if it was possible on realms too but I dont see a way to insert it in the middle. Thanks again.
I got the 2.0.1003 launcher running and created a new profile. I think I found the mistake - the user ID in the new profile format was stored at 'account' key, not 'profile', so I was parsing the wrong thing. Please update and check again if it works for you now.
I'm user 1.8 vanilla client trying to join a 1.8 server and it kept coming up with a massive error message on Minecraft so I tried typing mcb_update 1.8 and now it just keeps saying "Failed to verify username" on Minecraft. PLEASE HELP I really want to use this.
Hello @EditorMatt I have had this happen when your minecraft id needs to re-authenticate or the authentication servers are down.
Solution for me was to log back in the normal launcher without MCB and as soon as I could connect to the server, log back off and then use the normal MCB process to make the connection. Hope this helps.