This is a known issue with the program and we are trying our best to work on fixing this.
Here's two temporary fixes that may help:
- Quit and reopen the app
- Uninstall any custom soundpacks that you don't use
- Make sure that normal Mechvibes isn't also open alongside of Mechvibes++
- You may not have enough system resources (RAM or CPU power) to process both your game and Mechvibes++ at the same time
- Make sure that Mechvibes++ is running as Administrator, they may just be conflicting with one another.