iTunes: Can't Share iTunes Library between Different Users on the Same Machine

[spetznatz]

I moved my iTunes Library from my main admin account (~/Music/iTunes) to /Users/Shared/iTunes. From what I've read, from the Shared folder, the iTunes Library should now be accessible by any user on my Mac Mini. In my 2nd admin account, I open iTunes with the Option key held down and navigate to /Users/Shared/iTunes, but get the message 'The iTunes Library.itl file is locked, on a locked disk or you do not have permissions for this file'.

Even if I do a 'Get Info' and change the iTunes Library.itl file permissions to 'Read & Write' for the 2nd admin account, I always get this same error message. I've even set 'Everybody' to 'Read & Write' (I'm the only user of this machine) but the problem still persists.

Any idea what's going on here? (Mac Mini 2012, High Sierra 10.13, iTunes 12.7.8)

TIA,