Those who encountered the FMPAC issue in previous releases of fMSX will be glad to know that a new update has been rolled out. According to Akop Karapetyan, fMSX version 3.5.2 contains the following fix:

* Corrected MSX Music/MSX Audio labeling in System settings - MSX Music now correctly refers to FMPAC/YM2413 chip; MSX Audio refers to Y8950 chip. If the emulator was previously freezing with FMPAC audio, double-check to make sure MSX Music is enabled (disable MSX Audio to gain some extra speed) and try again

Make sure to read the readme file included in the download before you install it.