This question is just a sanity check. I wanted to factory reset a MacBook Pro (mid 2014) model. I first searched the standard tutorials and such, and have the core steps down:

  • back up stuff
  • log out of everything
  • command + R on restart to get to the startup menu
  • click disk utility
  • click your partition
  • erase and reformat (to macOS Extended or APFS)
  • reinstall macOS (need internet for this)

In the myriad of tutorials for this there are a few images showing each process.

In particular when selecting one's partition it often has the little arrow drop down and the partition is not grey-ed out.

When going on this mac to the same screen, there is no arrow, it just has "Internal", then Macintosh HD (with no drop down arrow). This partition is greyed out, but I can still erase it...

Before doing so I just want to make sure that this isn't something abnormal.

  • You could try the 3rd party app Mountain. appgineers.de/mountain. It gives you better control of all your volumes. It's not free but may have a free trial period.
    – Natsfan
    Jan 3, 2019 at 15:41

1 Answer 1


Unmounted partitions appear greyed out but are still erasable, so you could try mounting the partition.

I believe the partition would not be mounted if it's hidden. I'm not sure whether it's possible to hide your base system partition though, and I don't know why you don't see the usual dropdown.

  • I appreciate the input. How would my main system not be mounted?
    – SumNeuron
    Apr 25, 2018 at 6:00
  • I don’t know. I just tested by booting into the recovery environment on a family member’s Mac, and the main hard disk showed up as mounted. Are you factory resetting the Mac because of a problem with it? FWIW, the erase process unmounts the disk anyway before it begins so I don’t think it’s likely to cause any problems for you. But I speak only as a Mac user and enthusiast for 30 years, not as someone holding any macOS-specific certification or in-depth knowledge of this issue. Apr 28, 2018 at 16:15

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