My main hard drive is not bootable anymore

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Level 1

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My main hard drive is not bootable anymore

Hello everyone,

This just happened yesterday. My Mac crashed. Screen went black and it didn't react to anything. I tried restarting, but it wouldn't find a disk to boot from. It did find both of the disks I have in, but neither of them were bootable. I tried fixing them with disk utility. No errors. Couldn't repair permissions from the boot disk as it's not bootable anymore.

I thought, no problem, let's just reinstall Yosemite on top of the old installation. Booted from the recovery partition and that only had Mountain Lion on it! That wouldn't install as it detected that my main disk has a newer version installed. No idea why there wasn't Yosemite or even Mavericks on the recovery partition.

Next I connected a spare disk I had with USB and installed Mountain Lion on it. Booting from that and trying to install Yosemite on my main disk gives me an error telling me I don't have enough space on the main disk for the installation. Everything is still ok in disk utility (apart from not being able to repair permissions), I can access all the files just fine, but the disk is not bootable.

Can I fix this somehow without erasing the disk completely? And also does anyone have any idea what could be causing this? I guess I could erase everything and recover from Time Machine backups, but somehow I do not trust that those are ok either as my problems have been rather weird.

MacBook Pro (15-inch Mid 2012), OS X Yosemite (10.10.4)

Posted on Jul 23, 2015 4:33 AM

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Answer 1

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greg sahli

Level 7

25,508 points

Jul 23, 2015 7:56 AM in response to skip3

Two more generic things to try -

Resetting the System Management Controller (SMC) on your Mac - Apple Support

OS X Yosemite: Reset your computer’s PRAM

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Answer 2

greg sahli

Level 7

25,508 points

Jul 23, 2015 4:41 AM in response to skip3

A bit confusing - did you boot into Recovery or not?

Sounds like you went to Safe Mode instead?

I wouldn't expect anything important from repairing permissions -- did you try repairing the hard drive?

You can only use Disk Utility to repair the main (boot) drive when booted from some other source - that's why Apple gave us the Recovery partition as a second boot source.

PS - It does sound like the drive is failing.

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Answer 3

skip3 Author

Level 1

1 points

Jul 23, 2015 5:06 AM in response to greg sahli

Thanks for the reply Greg and sorry for making a confusing first problem post. I seem to be very good at that. 🙂

I did boot into the recovery partition, at least that's what I think. Held down cmd + r while booting and it went there like before. I don't know what safe mode is. Had the 4 options there: restoring from Time Machine backup, reinstalling OS X, getting help online and Disk Utility.

I tried repairing the disk. No errors, so it did nothing to help solve this. I just mentioned the permissions repair because I think that's related to it as you can't repair permissions on any other disk than a bootable one. And now that I'm running the computer from a USB drive with Mountain Lion on it, the old boot disk with Yosemite on it works fine, just isn't bootable (apparently, I don't know how to check this, but it won't boot from it at least).

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