Recover items in folders with red minus sign - Time Machine

The red minus signs indicate a file permissions issue. You can change the ownership of the files using Terminal.

Something like this:

sudo chown -R user:staff /Volumes/<your timemachine drive>/<backup>/Users/<username>/Music

Where user:staff equals your current username:staff and you insert the correct full path to the Music folder.

The command will change the ownership to your current user and do so recursively down through all the files within the Music folder. Then those red minus indicators should disappear.

You could also apply the ownership to /Users/<username> and that will do your entire home directory but it will likely take a lot longer to complete than the Music folder alone.

Why don't you use the TM app and navigate to that location to pull the data you want? I don't believe you should be using the Finder or the Terminal to navigate a TM backup due to how TM links the files for the backups.

If you still see the files/folders locked with the red dash, then create another macOS user account and try again.

I would not make any permissions changes to the TM backup itself as you risk corrupting the backup.

If you insist on continuing the current method to access the files, then use the third party app Carbon Copy Cloner to navigate to that location since it will ask for admin privileges which will allow it to see any file regardless of the permissions. You can also just copy that locked folder to your home folder which should automatically change the permissions to your current user (you will be prompted for your admin password). Or if you are navigating with the command line, then elevate yourself to root with:

sudo  su  -

For reference:

sudo chown -R user:staff

Means:

Super User Do Change Owner Recursively with this specific username and group. Where user is replaced with your username. The -R is recursive from this folder and all items within that folder and all sub-folders and files.

The sudo will prompt for your user password.

Copying from Time Machine to local disk is required because Time Machine files are read only (my mistake in the first suggestion). In this example, the username must have varied or if the same username as the backup, the UID number for the user accounts didn't match. Every user has a unique UID number. The first admin user created on a Mac is always UID: 501 and the next user would be 502, etc.

Try using the sudo chown -R user:staff command again on the local copy you should definitely be able to change the permissions locally.