I have a late '10 MacBook Air with 64gb ssd, it was getting very slow and very full so I decided to wipe and start afresh. I followed some online instructions, signed out of everything then erased the drive. The MacBook did its thing and updated via Wi-fi then I came to the point of installing Lion OS X. My problem started when I was asked to select a disk to install the os, there wasn’t one to choose. When I look on the Disk Utility, left hand pane shows 60.67gb Apple ssd TS064C Media with a sub heading of disk0s2. If I click on this it states Not mounted, verify disk states Verify volume failed:Unrecognised file system. Under this in the left pane I have disk1 with a sub heading of Mac OS X Base System. This amounts to 1.39gb. My question is how do I get the Mac to recognise the drive to reinstall Lion? Any help would be massively appreciated. Thanks

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    What OS was it running prior to this? If it was High Sierra [which it's capable of] then it may be formatted as APFS, which Lion cannot read. In which case, first thing to do is reformat as HFS+ – Tetsujin Oct 18 '18 at 13:41

I fought with an early Air that had been fully wiped by a well-meaning (but clueless!) IT person - he wiped not just the user partition (which I had already erased!) but also erased the reinstall partition. The only thing that worked to fix it was to find an original install image for the computer, place that on a bootable USB drive, and run from there, reformatting the internal drive as HFS+ in the process. If you can see the drive in Disk Utility, you should be able to reformat it.

If the drive WAS converted to apfs, you may need a newer version of Disk Utility to fix the format before you can drop to the Lion installer and start over. Use a bootable drive with macOS High Sierra or Mojave diskutil, dropping to command line to convert back to HFS+.

diskutil list to locate the APFS container

diskutil apfs deleteContainer /dev/disk#s# to kill the APFS container (replace disk#s# with the appropriate disk and partition)

diskutil eraseDisk JHFS+ "Disk_Title" /dev/disk# to reformat the now-destroyed APFS container

See here for more detailed info.

After that's done, you should be able to use the Lion installer to see and select the newly-recreated HFS+ partition as the install target.

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