FS9 had an mp3 file for the music. I had a few rock songs that were at least loosely related to aviation that I would rename and drop into the file folder for that sim.
Since I can’t change out the music here, the only reason I leave it on is to hear when it goes from the bootup slides to the main home screen. I’m usually in the middle of cooking a bag of popcorn and pouring myself a “beverage” when that transition happens.
Same, I dont like music in any of my games wether in-game or menu music. So if the game allows it to be disabled thats the first thing I do. I dont like listening to any eternal sources of music (like YT etc) while playing either. I know im in the minority as my friends think im weird lol. It just destroys immersion for me.
The marshal calling the sim to boot…
Love the intro and background music. Not sure I find it relaxing anymore as I’m grateful to start a flight without a CTD but I will always keep it. It does kind of signify ‘this is my time, finally’ 
For some reason the default intro music always makes me feel sad.
Its conveying a “look back, this has been your life so while the sun is setting down at least try to enjoy the beautiful sunset view.” mood to me.
That’s the exact reason why I leave it deactivated.
I don’t care for the music. It seems to me it should be live ATC from your favorite airport – always different – informative – get you in the mood for flying.
Quite honestly I have only been playing for a month now, but initially found the music a little “blue”, almost kind of depressing so I turned it off.
Well said, agreed.
Make me sleepy 
For me the music is annoying. Not really the style i would prefere while flying so i took the volume down and use spotify if i need music. For now since i am getting started i enjoy the sounds of the engines and planes without any music. But as a musician i can say the music can be better. 
Turned the music off on day 1, very irritating.
Not just MSFS do the same with DCS and IL2 as well.
Same here. Done that with all computer music. I want music only when I’m driving or hanging around at home. I have about 2,000 music tracks on my computer and phone for that.
MSFS has music? Who knew? 
Does anyone know that it’s been maybe 15 years since Microsoft Jigsaw’s music? p.s. Maybe that’s why I’m trying to put the plane back together after a crash…
Im rocking the legacy music now. Brings back my days of FSX.
I’m similar to most of you folks, my in-game music is set to zero. If I want music I grab my mp3 player and listen to that otherwise I just enjoy the sounds of the ambiance
I’d like to have some more choices in music to honest, maybe include the TopGun theme, maybe some regional music themes? A nice variety.
OH and only on the startup/start flight pages, not actually in flight.
Not a fan of that either. However, that’s for the FS newbies to keep them interested during Discovery Flights. Perhaps we could get some further options under music settings?
I just want to be able to select ~20 songs on my PC that will act as my MSFS menu music for some much-needed variety!
Hm, music packs could be a new DLC category for the Marketplace! 
Yes the music of flightsim does makes me happy because when i hear it, it means that i have time to whatever i want to do in the sim. One of the many favorite things i like to do with my spare time.