iTunes libraries won't open in Apple Music - It just upgraded me from Mojave to Big Sur. And now, I cannot open any of my iTunes libraries!
All the libraries are gray after it upgraded me from Mojave to Big Sur, automatically skipping Catalina.
I cannot open ANY of my iTunes libraries! They are all gray. They are on an external HDD, formatted to Mac OS Journaled. (At some point, Apple started reformatting people's system drives to a new type.)
I googled for an answer, but the only one I found that seemed related (that I tried) didn't work: The libraries are grayed out. This was all I found, so far (which I already knew):
"Switch libraries with the Apple Music app in macOS
If you have multiple iTunes libraries, learn how to switch between them in the Apple Music app in macOS Catalina or later.
How to switch iTunes libraries
- Press and hold the Option key, then open the Apple Music app.
- In the window that appears, click Choose Library.
- Select the iTunes library that you want to switch to.
- Click Choose.
Published Date: July 20, 2021"
MacBook Pro 15″, macOS 11.7