"Missing Operating system_ " After installing Yosemite

THANKS Loner T,

Yes, Yes , Yes , and Yes are the answers to your questions. I successfully recovered boot camp partition and all my windows files thanks to your help. I opted for the default values and it worked. I really appreciate your help thanks for being an amazing human being.

Regards,

Abughareeb

Here it's =>

As I mentioned above everything is back to normal again. Let me know if I need to make any modifications.

Thanks

Very nicely done. Thanks for the update. I suggest a backup of OSX and Windows as a baseline for future upgrades.

Will do thanks again Loner T.

Sorry to bug you again Loner T, but I am unable to log back in to OSX. I can see both partitions on boot up. Windows works fine which I am writing to you from. However, I can'tt boot into mac os x. When I select Mac OSX I get to the grey screen once the progress bar reaches the end a "no entry" sign comes up. I tried going to recovery mood to see what is going on. One thing I can see raised suspicion is the size of my HD which is 500.11 GB and that is it.

Please help 😕

1. If you look at the mediasize value (500107862106 sectors), it is roughly 500.11 Gib as specified by the manufacturer.

2. In Control Panel -> System -> Boot Camp, can you select OSX and bring up OSX?

3. If you power-cycle your Mac and hold the Alt key, do you get OSX as a choice? If selected, what happens.

4. In Recovery Console, can you take a photo of the gpt -vv -r show /dev/disk0 in Utilities -> Terminal to check if it matches the one you posted earlier.

5. Do you see an image like this one ?

Hi Loner T,

Here is what I found so far:

1- OSX doesn't show up in Control Panel -> System -> Boot Camp. I can only bring the partition up when I click alt during boot process which brings both partitions. I then chose Macintosh HD as my boot drive. It lets me do that after which a gray screen with a gray progress bar comes up until the end of that progress bar. After that a gray screen with a right in the middle of the screen shows up.

Here is the disk utility and the execution result of the cmd you asked for =>

Please pardon the images resolution I took them with my cell phone and had to resize to get them under 2MB.

Thanks for the help.

If you notice the long string after GPT 2 is different between when OS X was working and what it is now. This happened because when Gdisk was used to create the Hybrid MBR, for GPT 2 the hex code used was 'AF' (JHFS+), but it should have been 'AF05' (CoreStorage).

Do you have another Mac and TB/FW cable and connector?

I do have an older mac but I don't have the connector. What is the scenario ?

The method uses Target Disk Mode as described in Share files between two computers with target disk mode - Apple Support.

The other option is to install OS X on an external disk, install GPT Fdisk and boot from it to fix this. Please see OS X: Installing OS X on an external volume - Apple Support.

I will do the second option. I am going to follow the instruction to download and boot from the external drive. What should I do after that Loner?

Please give me the steps that follows.

Thanks

Install GPT Fdisk on this external disk as well. Run Gdisk the way you did for deleting/adding GPT 4, but the difference is that the partition type will be changed from AF (JHFS+) to AF05 (CS) for GPT 2.

What about the other ones ? Because it did ask me the types for all of the. After that I could answer for Y/N for bootable flag.

You are not trying to create a new MBR, but if you look at the Gdisk menu, the following steps will let you change the partition type of a specific partition.

sudo gdisk /dev/disk0

GPT fdisk (gdisk) version 0.8.10

Warning: Devices opened with shared lock will not have their

partition table automatically reloaded!

Partition table scan:

MBR: hybrid

BSD: not present

APM: not present

GPT: present

Found valid GPT with hybrid MBR; using GPT.

Command (? for help): t

Partition number (1-4): 2

Current type is 'Apple Core Storage'

Hex code or GUID (L to show codes, Enter = AF00): AF05

Changed type of partition to 'Apple Core Storage'

Command (? for help): p

Disk /dev/disk0: 500118192 sectors, 238.5 GiB

Logical sector size: 512 bytes

Disk identifier (GUID): 22749ACF-207D-458E-B255-5DF02C39DC2D

Partition table holds up to 128 entries

First usable sector is 34, last usable sector is 500118158

Partitions will be aligned on 8-sector boundaries

Total free space is 1325 sectors (662.5 KiB)

Number Start (sector) End (sector) Size Code Name

1 40 409639 200.0 MiB EF00 EFI System Partition

2 409640 250801735 119.4 GiB AF05 OSY-MBP13

3 250801736 252071271 619.9 MiB AB00 Recovery HD

4 252071936 500117503 118.3 GiB 0700 BOOTCAMP

Followed all the step but I still get the same "no entry" sign

- I can't see the OSX partition in boot camp tool in windows.

- I can only see the Macintosh HD when I hold option during boot. Then i would get the sign?

I double check all the steps , but I still get the same result .

Please Help