Can I know the technical specifications of a Mac mini without an OS?
You’ve got a few options here:

Lookup the machine exact hard drive capacity by entering the serial number on the Every Mac website.

Boot the Mac Mini while holding down the ⌘ CommandR keys to enter recovery mode and then chose the Disk Utility option (normally at the bottom of the menu) this will show you the capacity of the installed hard drive.


I’ve never tried it before but I would also expect Time Machine to warn you if you attempt to restore your backups to a disk that’s too small.