Deleted my Mac hd volume on accident with no backup. Can I fix this without erasing everything?

Salmonpilot wrote:

Deleted my Mac hd volume on accident with no backup. Can I fix this without erasing everything?

?

And why would you do that...is there some bigger issue(?)

ref: About the read-only system volume introduced w/ macOS Catalina - Apple ...

https://support.apple.com/en-us/HT210650


Big Sur goes one step furthere w/ a “snapshot” of the current system for its (SSV) Signed System Volume, as you see in the list. This is the new normal as well. This would be the 'Macintosh HD'

How to reinstall macOS from macOS Recovery - https://support.apple.com/en-us/HT204904

Do not wait for a catastrophic failure to get the backup religion:

3-2-1 Backup Strategy: three copies of your data, two different methods, and one offsite.

If you install the OS on a new Macintosh HD, it won’t inherit the old Data volume. You would need to migrate the old to the new. This would require that you have enough free space to duplicate everything on Macintosh HD - Data.

Building on @leroydouglas posting 3-2-1 Rescue Plan

Do I have a Rescue Plan In-Place. This comprises having 3 Backups using 2 methods and 1 Off Site incase of Theft, Loss or Natural Disasters. A Time Machine Backup  is very useful and can be used to Revert to Previous Working macOS. For addition purposes - two Tested Bootable Clones each to separate external drives. This is insurance incase of your situation. At least one Tested Clone and / or Time Machine Backup should be Off - Site

I have used Carbon Copy cloner many times and it can restore the data vol, only. I would backup this data volume then reinstall the OS like Barney suggested and see if you can access the data vol. If not then perhaps you can just clone the saved data vol. back to your main drive after.

If all you deleted was the Macintosh HD volume, and you still have Macintosh HD - Data, you don’t need a backup or anything similar. Your data is stored on Macintosh HD - Data.

I don’t know whether installing the OS will use the existing data volume, or create another.

If you have a backup, then it won’t be an issue.

Just create a new volume and install the OS on that.

If you don’t have a backup, you may be able to use the Restore function in Disk Utility to make a copy of the Data volume.

I don’t think reinstalling the OS will overwrite the remaining Data volume, but it could

yes the relocated files Big Sur creates.

If you had stored files at the top level of the hard drive, they would be moved into /Users/Shared/Relocated Items. You should be able to access that folder in the Macintosh HD - Data volume.

The installer will also move system configuration files that were changed, such as the Apache web server, SMB configurations, etc. If none of that applies to you, there is likely nothing in that folder you care about.

Not something I have tried, but create a new Volume named Macintosh HD.

Install macOS onto that volume from Recovery.

No idea. You’d have to describe how they were relocated in the first place.

You could copy the Data Volume to an external drive, then try to migrate from that after removing the old Data Volume.

Are you referring to the Relocated Items folder that Big Sur creates?