Reinstall Mac OS X Without Recovery Mode | Mac Doesn't Boot Normally

Can I reinstall it with Target Disk Mode?

And also erase the disk?

MacBook Pro, null

Posted on Jul 21, 2016 3:27 AM

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19 replies

Jul 21, 2016 11:14 AM in response to Hyperion Proteus

Cloning creates an exact image of a drive and makes it bootable so you can boot from it.


If I understand your situation, you have a Mac that you can't boot from the internal hard drive for some reason.


Do you have a USB thumb drive with the OS X Lion installer? If your answer is no, can you create a USB thumb drive Recovery HD from your other (good) Mac that has OS X Lion by using the OS X Disk Assistant?


The only way I know how to clone an internal hard drive to an external drive without a 3rd party app is by booting a Mac into a Recovery HD then use Disk Utility's Restore feature. Restore does a block-copy (clone) from a Source drive to a Destination drive.


Since you have no Recovery HD on the bad Mac and IF you can create an OS X Lion Recovery HD on a thumb drive from the OS X Disk Assistant, then you can plug that into your bad Mac, restart while holding down the Option key and select the thumb drive to boot from. We can go from there if you're able to do this.


If you're able to boot your bad Mac using an external source then you should be able to use Disk Utility to try to repair your bad Mac's drive before you resort to reinstalling OS X or erasing and reinstalling.

Jul 21, 2016 10:26 AM in response to keg55

How can I back up/clone the HDD with Target Disk Mode?

Can I just reinstall the OS X and not erase the HDD?


My biggest problem is my Mac doesn't boot normally.

  • So will just and only reinstalling the OS X fix it?
  • Or can erasing the disk and also reinstalling the OS X fix it?

Or both options will work either what I choose?


Recovery Mode does work and I can enable it..

But the disk is locked and I can't reinstall the OS X.

Jul 21, 2016 6:42 AM in response to Hyperion Proteus

I have used Target Mode several times to install OS X on a Mac Mini. Specifically OS X 10.8.5.


I connected my Macbook Pro Retina running 10.8.5 to the Mac Mini with a Thunderbolt cable.

Then, I booted the Mac Mini into Target Mode by pressing/holding the T key at start up. From the Macbook Pro Retina in Finder, the Mac Mini's Macintosh HD showed up and I used Disk Utility to erase it then install OS X Mountain Lion.


Make sure the Source Mac has a version of OS X equal to or earlier than what you want to install on the Destination Mac (Target Mode). For example, if you try to install OS X Yosemite from a Source Mac running OS X El Capitan, you may get an error saying you can't install an earlier version of OS X.

Jul 21, 2016 7:22 AM in response to Hyperion Proteus

Hyperion Proteus wrote:


So the other Mac, which will be the Source Mac, should be OS X Lion if I want to install OS X Lion to my Mac?

The SOURCE Mac is the one you're going to use to install OS X to the Target Mode Mac (DESTINATION).


So, your Source Mac needs to be running OS X Lion or earlier (e.g. OS X Snow Leopard) to be able to install OS X Lion on your Destination Mac (Target Mode Mac). Hope this makes sense.


But remember, you need to connect the two Macs with a cable. In my case, I used a Thunderbolt cable.

Jul 21, 2016 10:36 AM in response to Hyperion Proteus

In Target Mode, that Mac looks like an external hard drive on the other Mac.


You can also clone the Mac using 3rd party apps like Carbon Copy Cloner and SuperDuper!.


You can reinstall OS X on the Mac without erasing it and this will only affect the OS and not harm your user accounts, data or apps. Reinstalling OS X over itself has been known to fix issues. You might even try Disk Utility from the good Mac to repair the bad Mac if after a Verify, you're seeing errors. You can also erase the bad Mac and reinstall OS X which can also fix it.


You should be able to unlock the Mac's drive via Disk Utility from the good Mac. I assume it's locked because it's encrypted from enabling FileVault.

Jul 21, 2016 8:21 PM in response to keg55

You said I'm able to unlock the bad Mac's drive via Disk Utility from the good Mac.


After I unlock it using Disk Utility on the good Mac..

Does that mean if I enable Recovery Mode on my bad Mac, will the disk appear unlocked on my bad Mac (In Recovery Mode)?


Or will it still be locked on my bad Mac and/but only appear unlocked on the good Mac? -- Don't mind this if you don't understand.


Hope you understand.

Jul 22, 2016 5:27 AM in response to Hyperion Proteus

I'm sorry but I'm confused by all your questions.


If you enabled FileVault on your Mac, the drive is encrypted and has to be unlocked every time you boot the Mac. So, did you enable FileVault on the Mac you're trying to fix?


You mentioned in one or your prior posts... "But the disk is locked and I can't reinstall the OS X.".


Also, in that same post you mentioned... "Recovery Mode does work and I can enable it..".


I don't know what to tell you anymore.

Jul 24, 2016 4:26 AM in response to keg55

keg55 wrote:


I'm sorry but I'm confused by all your questions.


You mentioned in one or your prior posts... "But the disk is locked and I can't reinstall the OS X.".


Also, in that same post you mentioned... "Recovery Mode does work and I can enable it..".


I don't know what to tell you anymore.

Okay..

So I turned on my Mac and enabled Recovery Mode.

The window Mac OS X Utilities appeared.


There are four options I can select.

I selected Reinstall Mac OS X.

At the end of the process/instructions..

It told me to select a disk where I want to reinstall the OS X.


Two disks appeared: Recovery HD and Macintosh HD

Both disks are locked.


So now I'm trying to unlock the disk using the good Mac..

Which you said, "You should be able to unlock the Mac's drive via Disk Utility from the good Mac" - 10:36 AM Response).

So that after unlocking it, I'll reinstall OS X with only my Mac (Without Target Disk Mode).


If what I said above doesn't work..

I'll reinstall it with Target Disk Mode.


Sorry for the confusion.

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Reinstall Mac OS X Without Recovery Mode | Mac Doesn't Boot Normally

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