# FreeBSD Install DVD corrupted my Mac OS X harddisk



## aurora (Mar 15, 2013)

Recently, I have tried a FreeBSD 7.4 i386 Install DVD just to take a look at some screens of FreeBSD on my Mac mini Intel 2006. After seeing several dialog screens, I was going to try the Live CD feature of FreeBSD, just to take a look at the contents of its harddisk on which Mac OS X Leopard is installed. And I did see them and later I ejected the FreeBSD Install DVD without changing anything on Mac mini's harddisk.

But after restart I found that Mac mini would not boot Mac OS X Leopard. Apparently, some code on FreeBSD DVD have tampered with someting on the Leopard harddisk.

When I checked the harddisk using another (and working) Leopard on a firewire connected harddisk

`# gpt -r show disk0`returned this: 







which is exactly the same with a working Mac OS X harddisk, except one section:

On a working Mac OS X harddisk, the first entry is "pmbr" , whereas it's "mbr" in my unworking OS X harddisk.

Furthermore I noticed that this unworking harddisk, though it shows 2 partitions in gpt, does not show up as ./disk0s1 ./disk0s2 under /dev, but it shows up simply as ./disk0

If only can I make it show up as ./disk0s1 ./disk0s2 under /dev, I think I can fix it. Is there a way to do it that way?


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## dave (Mar 18, 2013)

What were the dialog screens you saw?  How did you respond to them?


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## SirDice (Mar 18, 2013)

aurora72 said:
			
		

> Recently, I have tried a FreeBSD 7.4 i386 Install DVD just to take a look at some screens of FreeBSD on my Mac mini Intel 2006.


FreeBSD 7.4 is end-of-life and not supported anymore. 

http://www.freebsd.org/security/#unsup

I would suggest installing something like Virtualbox and playing around with it.


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## break19 (Mar 18, 2013)

The handbook specifically tells you to back up your data. Unfortunately, if you did not follow the directions here, and failed to back up your data, then you just need to accept the fault, and move on.

Either reinstall your OSX operating system, or, if you still want to use FreeBSD, then keep it, and we'll happily help you learn.  BUT, failure to even read the existing documentation will make things much more difficult for you.. and for us.

"I installed an operating system on a computer with an existing operating system and it corrupted the existing operating system!" And you blame the operating system?


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## kpa (Mar 18, 2013)

> later I ejected the FreeBSD Install DVD without changing anything on Mac mini's harddisk.



Note the above. Just booting off the install disk and looking around in the Fixit environment shouldn't have changed anything on the disk.


Intel Macs are quite strange though, they have both MBR and GPT partition tables because of how bootcamp works.


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## Paul47 (Mar 19, 2013)

Since you suspect the problem is in the MBR, why not use dd to transfer both a working "pmbr" and this "mbr" to a flash drive, then look inside them with a binary editor or dump or something to understand what differences there are. Maybe you can fix the one that does not work. Maybe it's as simple as copying the pmbr over the mbr although you have to make sure the partition table points into the same places.


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## aurora (Mar 19, 2013)

dave said:
			
		

> What were the dialog screens you saw?  How did you respond to them?



I browsed as far as to the "slicing editor" screen where you select partitions and assigning FreeBSD's /, /tmp, /var, etc. to the partitions. I quit that screen without selecting and assigning anything. 

It's ok if FreeBSD did some modification on the harddisk because I have its backup. 

I wonder if it's possible to make the Mac OS X bootable againg without copying the backup 
or installing it from scratch.


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## kpa (Mar 19, 2013)

Find an installation disk for OS X 10.5 or 10.6 and boot from it and go to disk utility, it should be possible to repair the disk from there.


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## aurora (Mar 19, 2013)

kpa said:
			
		

> Find an installation disk for OS X 10.5 or 10.6 and boot from it and go to disk utility, it should be possible to repair the disk from there.



Thank you for the suggestion. I had tried that, and it didn't work because the repair option in Disk Utility was not selectable (grayed out). I guess that's because the harddisk's partitions cannot be mounted by Mac OS X.


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## SirDice (Mar 19, 2013)

aurora72 said:
			
		

> Thank you for the suggestion. I had tried that, and it didn't work because the repair option in Disk Utility was not selectable (grayed out). I guess that's because the harddisk's partitions cannot be mounted by Mac OS X.



If you boot the install DVD/CD the partitions aren't mounted.


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## aurora (Mar 19, 2013)

SirDice said:
			
		

> If you boot the install DVD/CD the partitions aren't mounted.


That's true. But the install DVD must have done something on the partitioning scheme. As far as know, that doesnt require partitions to be mounted.


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## SirDice (Mar 19, 2013)

I meant boot the OS-X install CD/DVD and using the repair utility.


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## aurora (Mar 19, 2013)

Disk Utility shows the harddisk as having no Partition Map Scheme, here's the screenshot:





 I got this shot using Mac OS X on a Firewire harddisk, but it's the same with the OS X Install DVD.


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