So my mac HD started playing up and then refused to work, would not boot.
Tried recovery mode but it wouldn't allow me to run first aid on the Macintosh HD drive.
Created a MacOS USB boot up stick by formatting a blank USB stick then using the recovery option to install MacOS on it.
Plugged it in, rebooted and held the command (cloverleaf) key.
Mac then displays the drives from which you can boot
Chose the USB stick and not MacintoshHD.
and it is taking forever.
It took me through all the usual options "set up appleID" and so on which I either skipped or chose default.
Then it just went black with the beachball.
Now it's just black with the arrow/pointer.
Doesn't appear to be doing anything..

So is it because MacintoshHD (internal HD) has issues that the USB booter is not able to finish?

EDIT: additions in italics

  • 1
    It's a bit unclear as to precisely what you did. 1. 'cloverleaf' is Cmd, not Opt. 2. 'Chose the USB'… chose it to do what. If you chose it to boot it would present installer options. What did you do at these options? If you got to AppleID then presumably you have attempted to install a new OS on the HD. Did you fully erase first? If yes, then that would hint that the drive itself is failing. Did you run Disk First Aid at any point? What was the result?
    – Tetsujin
    Commented Feb 1, 2021 at 18:01
  • 1
    We had an old iMac where some kind of hardware issue seemed to develop with the Hard Drive. I was able to boot into a USB installer disk and create a usable bootable installation on an external USB hard drive. It wasn’t a good long term solution as it was very slow, but it is possible.
    – kal-al
    Commented Feb 3, 2021 at 1:02
  • thanks for the feedback, apologies for not being entirely clear, see italics for more info Commented Feb 3, 2021 at 14:11

1 Answer 1


Yes. Mac hardware is designed to boot from an external OS whether it’s an external drive, cheap commodity USB Flash thumb drive, network boot, internet recovery or direct attached disks. The startup manager governs which item is selected and you can connect the OS after you power on the Mac.

It even will search for a bootable drive if the last one stored in Non Volatile Ram (NVRAM) isn’t detected.

In your specific case, you would need to look at the startup logs for the OS to determine the issue or bring another OS to bear to rule out the first OS or drive you’re using. On slow USB media it can take dozens of minutes to boot, but on fast external media, it should be minutes tops.

Also, a failing drive can bring down the Mac and prevent booting from a known good OS so your option might be to remove the drive entirely (if feasible) to test that or have it repaired.

  • Ok so it worked in the end but it took an incredibly long time to do anything and in the meantime gave no indication as to whether it had hung or was completing something. Commented Feb 3, 2021 at 14:08
  • 1. Ran first aid on the MacintoshHD drive 2. deleted some old files from this drive to try and get it down to at least 5% free space 3. restarted booting from MacintoshHD 4. opened mail and got it to rebuild all mailboxes 5. emptied trash and did more clean up 6. it seems to be ok now but this was not a fun experience and took over 6 hours to get it working again Commented Feb 3, 2021 at 14:09

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