1.21.7-rc2

### Operating System

Windows

### Description of bug

when I create a new instance with 1.21.7-rc2 and launch it, it causes multimc to close.

### Steps to reproduce

create an instance of 1.21.7-rc2 and launch

### Suspected cause

0 idea

### This issue is unique

- [x] I have searched the issue tracker and did not find an issue describing my bug.