Startup failure, tried reinstalling OS but disk couldn’t mount/no free space?

Question

Startup failure, tried reinstalling OS but disk couldn’t mount/no free space?

My MBP 15 was frozen so I turned it off via the power button. It now fails to boot and loads OS Recovery straight away.

When I try reinstalling my OSX (Mojave), everything looks fine until I have to select a disk to “unlock”. I only have Macintosh HD, so I selected it. However, when I press the “unlock” button nothing happens. The back button works, so I’m not sure what’s going on. What should I do next?

Other information that might be helpful:

-I’ve tried resetting the PVRAM, didn’t work

-when I include my external time machine, it tries to install Mojave, internet recovery installs Yosemite

-when I go into disk utilities, Macintosh HD is “unmounted”, and when I press “mount”, nothing happens. On internet recovery, the same thing gives me “Alert: couldn’t mount disk”. Clicking “Repair” gives me “Alert: Partition map repair failed while adjusting structures to fit current whole disk size.”

-it says there’s 0 free space on my Macintosh HD drive, but usually there’s 5-15gb free after boot up. Is there a chance when I turned it off none of the caches cleared like normally, making the drive inoperable? And if so, what should I do? I tried deleting stuff via Terminal but only see “Library” included.

Thank you so much!

MacBook Pro 15″, macOS 10.13

Posted on Feb 10, 2021 12:33 PM

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Answer 1

Best reply

etresoft

Level 8

47,350 points

Feb 10, 2021 12:48 PM in response to wild-blue-yonder

wild-blue-yonder wrote:

usually there’s 5-15gb free after boot up.

That means your hard drive is, or rather, was, full. It is now corrupted and unrecoverable. You will need to erase it, reinstall the operating system, and restore from backup.

If you were backing up the system with only 5 GB free. There is a good chance the restore will fail too. If you get lucky and can get the computer working again, you will need to immediately archive any large and/or older documents that you don't need. You will probably need to purchase an external hard drive for this. Do not use Time Machine. Time Machine is a great backup, but files you delete will eventually be deleted from Time Machine too. Plus, as your computer is now dead, Time Machine is the only chance you have of recovering those files. You don't want to take any chances with it.

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Answer 2

steve626

Level 6

10,235 points

Feb 10, 2021 4:26 PM in response to wild-blue-yonder

As someone else has pointed out, you seem to have filled up the disk causing operating system malfunctions (probably could not page to disk among other things) and ultimately disk corruption.

IF YOU HAVE ONE OR MORE GOOD AND RELIABLE BACKUPS (Time Machine, or a "clone"), you CAN TRY to boot into Recovery and erase/reformat and then run Migration Assistant to bring back over files to your now mostly empty drive -- BUT ... you have to migrate less than there was before or else you will just reproduce the "overfill" condition and ruin the new system as well. You could try Migration Assistant just bringing over one administrative user and only files, no applications, no settings, nothing else. Then, assuming you can start up from the new system, immediately move large amounts of files taking up storage off the computer to an external drive. Make sure you have created at least 30-50 GB free space or a minimum of 20% free space. Then you can try to reinstall applications but watch this disk space carefully, never go that low or you will be back where you are now.

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