macOS (12.1) Music App (1.2.1.40) issues (won't start with music-window or at Fullscreen)

I had the same issue for a while on my M1 MacBook Air (same OS Version and Music version). Apple chat support t=asked me to do a bunch of weird stuff like holding the option key while opening the app, trying it in Safe Mode and reinstalling macOS. When even the reinstall didn't work, I gave up and decided to just live with the bug and wait for an update.

A few days later, I found a bunch of uninstalled apps' preference files taking up space in ~/Library/Preferences. I was too lazy to figure out which ones were uninstalled and which ones I needed. I went crazy and nuked all my preference files. Don't ask, I don't know what I was thinking.

The computer shut off and made me go through the setup assistant again a little while after that. Luckily none of my data was deleted. Believe it or not, this fixed it. It reset all my settings for every app though. the next few hours were NOT fun.

Warning = Try this at your own risk. Your mileage may vary. Please don't kill me if you lose your data. I absolutely do NOT recommend this. Try it only as a last resort.

I think reporting the bug at apple.com/feedback or through the Feedback Assistant app and waiting for a fix is the best thing to do. Try my way only if you are very frustrated and nothing else works.

Let me know if you find the plist that's causing the issue. I found that deleting com.apple.music.plist fixed it for a while, but the bug would come back eventually. That's apparently not the cause though.

Good luck!

So, I did a bit more testing. This only happens if you quit the app while it's in fullscreen mode. if you take the app out of fullscreen and then quit it, it'll work fine. I've submitted dev feedback to Apple through the Feedback Assistant, with screenshots and steps to replicate it. Hopefully, a fix will roll out soon.

TL;DR there's something about fullscreen that messes with prefs.

I am having the same issue after the "native" Music app update. This bug started to happen after I quitted my Music app in full screen mode. I am using my Macbook Pro 14" M1 Pro to use the Music app now.

Hopefully the solution you tried wasn't to nuke ALL the preference files. Did you find the single file to delete and fix the issue? I too have the issue where after a restart Music will not return to fullscreen view without me putting it back in fullscreen. It appears as though Music is launching but staying hidden after restart. I've also noticed that some times Mail, which is also set to be in fullscreen will sometimes POP out of fullscreen for some unknown reason. It however IS in fullscreen after restart.

I'm not sure about the Mail problem you seem to be having. What I can tell you is that deleting com.apple.music.plist in ~/library/preference is the answer to the Music problem. After that, remember to not quit the app in fullscreen, and you should be good.

Unfortunately it didn't work for me. Removing that pref, keeping app running and doing a restart I get the app appearing not in widescreen along with a pop up window welcoming me to Apple Music with a button to "Start Streaming". I put it back in fullscreen, restarted again and its back to how it was., Went through the whole process twice and the same. Hoping for a fix in a future update.

Nice! My Mac was actually in the process of downloading 12.3 when this message came in so I was looking forward to it finishing and seeing for myself. Can confirm! Glad this one is off the list. Now....if I can just get my Apple Podcast app iOS issues addressed. 🤦

Update : This has been fixed with macOS 12.3

****! Your Music app is acting REALLY crazy. Apple is working on a new "native" music app in 12.2. Maybe that could fix it?

For me, I tried the solution that

JayanthSahasranamamula posted here, and it worked for me. I hope you fixed it now.