Why did a failed Catalina install, and restore to Mojave, yield a new disk volume Macintosh HD - Data
Why did a failed Catalina install, and restore to Mojave, yield a second, new disk volume Macintosh HD - Data?
The Catalina upgrade failed because of "an "opt" file couldn't be saved in Macinotsh HD." I tried three times and gave up.
I Restored to Mojave and now have a second disk volume, Macintosh HD - Data. Looking inside each of HD or HD -Data I can't tell which has Mojave in it. The HD volume has lots of grayed-out files.
But never mind; how do I cleanup this mess? Once I do that I'll deal with the "opt" file, which is invisible in the Finder but seen on "Search."
Thank you.
MacBook Pro 13″, OS X 10.11