How to restore Apple Mail messages and settings from other booting disk?

The external SSD Mac disk 1 booting iMac with the latest Mac OS X El Capitan got broken. It does not boot, but it is accesible (read only) when booting from other disk.

I have formatted a new external SSD disk 2, installed the latest Mac OS X El Capitan and used Migration Assistant to restore it with a Time Machine backup one month old.

During such Time Machine missing month I started configuring and using Apple Mail in disk 1. So, all Apple Mail settings and messages are in such broken disk 1 and not in the Time Machine backup.

Now I would like to update disk 2 to include such latest month of Apple Mail messages and settings available in disk 1, but missing from the Time Machine backup. I have tried to do it booting as root and replacing

/Users/~/Library/Mail

folder of disk 2 with the one of disk 1, which contains the updated Apple Mail messages from last month. But then Apple Mail in disk 2 opens yet does not show its main window (only its main menubar is shown), and most submenus are gray-dimmed. For instance, I cannot access Mail preferences submenu, etc.

How to do it?

Thanks.

Posted on Sep 6, 2016 9:22 AM