Whenever I accidentally hit my MacBook's Play/Pause key (F8), the device launches the Music app and automatically starts playing a song. This has been annoying me for a while. I usually have my MacBook's lid at an acute angle while working on an external monitor, and I don't always look at the keys I'm pressing when it's like this, so to be suddenly interrupted by music can be a real pace breaker. I also don't love the music app on Mac—it's slow, doesn't always work reliably, and even freezes sometimes. It's why I prefer to use Apple Music from my iPhone or my HomePod instead.
This annoyance sent me looking for a way to stop the Play/Pause key from launching Music, and it turns out that there are a few ways to do this.
Use a decoy music app
Music Decoy is a lightweight and simple utility that stops the Play/Pause key from launching Music. It does this by running a process with a similar name as the stock Music app, which tricks macOS into believing that Music is already running. Hence the name—Music Decoy. The app is a free download and does nothing extra, which means that it has no impact on system resources.
The problem is that this will disable the Music app altogether. You won't be able to use Apple Music on the Mac while Music Decoy is running. I don't mind this, but this may be a deal breaker for some. The advantage of this app is that the Play/Pause key continues to function for all other apps.
Disable the Play/Pause key altogether
You can also disable the Play/Pause key altogether using a Terminal command. On your Mac, open the Terminal app and run the following command:
launchctl unload -w /System/Library/LaunchAgents/com.apple.rcd.plist
Now, try pressing the Play/Pause key to confirm it's disabled. The key shouldn't work in any app. If that's a bit too extreme for you, you can reverse the change with the following command:
launchctl load -w /System/Library/LaunchAgents/com.apple.rcd.plist
There are compromises involved in both methods, but I prefer using Music Decoy because it keeps the Play/Pause button useful and gets rid of the annoying Music app.