Unfortunately I did not. I was expecting something from the Welcome to Nucleus Quick Start Guide when I de-authorized the Mac. It was a moment of instant regret. I should have been familiar with the Migration guide.
Time Machine is not recommended for backing up the Roon database. The only proper way to backup your library is thru Settings==>Backup.
OTOH, just because you unauthorized Roon on your Mac doesn’t mean that library is gone, unless you actually removed Roon from the Mac. If everything is still on your Mac, then simple reauthorize Roon over there. Do a Roon backup using the Roon procedure, i.e. not Time Machine, and then restore on your Nucleus, following the info in the link provided above.
I followed your suggestion and plugged a new SSD with a USB connector into the Mac mini, Authorized the Mac and did another backup. I reauthorized the Nucleus + and restored all the Playlists that were missing. Success. Thanks
Next problem: I set up backup on the new Nucleus + using the SSD drive. The path is Nucleus+ > G Drive SSD > RoonBackup. That is the same path I restored from but I keep getting a message INVALID PATH SPECIFIED. Any suggestions?
Am I correct in my understanding that the G-DRIVE SSD was originally used on the Mac, and you are now trying to use it on the Nucleus?
If so, if it was originally formatted as HFS/HFS+ (also known as “Mac OS Journaled”) on the Mac, then it will be a Read-only drive on the Nucleus - so cannot be used as a Backup destination. You would need to reformat it before it can be used.