It spent hours trying to rebuild my original setup but then would stop 2/3rds of the way through. Its not that Time Machine did not work from the start. I think because Catalina upgrade created the HD-Data volume there was no longer enough free space left to restore from Time Machine. I have very little free space now because of it. Had to reinstall Mojave and found that since then I cannot use Time Machine. Tried to restore Mojave using Time Machine and it failed - twice. I upgraded from Mojave to Catalina (solely so that my daughter could use PS4 controller in my Mac) and found my 32 applications would not work. I have unlimited ISP, would it be easier to re format and start again then re download films or is there a quick fix to tidy this up?

The other volume is not visible to the OS directly but is via disk utility or Carbon Copy Cloner or Apple TV app, this non visible volume has a tag diskname-Data and contains the films. The volume already contained info, I added Catalina to the external hard drive via the Apple installer and now have two APFS volumes on that single external drive, one that is visible directly to the OS, with Catalina. More adding another start up option than anything else. I decided to add Catalina to it as my main drive (iMac 2013 1TB fusion) is showing potential issues, running up to date Catalina. I have a particular external hard drive that I just keep Apple films on. I have a few other external hard drives with 'just in case' MacOS on (Mojave) and time machine that manage my backups. I have a backup plan and this particular external disk is not used in it. Missing data volume after adding Catalina on external hard drive To start I cannot find where I update my device info.

I erased macintosh hd