Okay, so something really strange has happened, and it's a doozy, so please bear with me.
Problem: I need to fix my hard drive's partition map
So let me fill you in on what happened here.
I have an external 3TB hard drive that I use for storage with my Mac Pro. It recently had 4 partitions on it. This is what the map looked like.
- Backup [OS X, Journaled]: 1.4TB
- Macintosh HD clone [OS X, Journaled]: 0.3 TB
- Yosemite [OS X, Journaled]: 0.5 TB
- Windows Bridge [FAT]: 0.5 TB
I had originally downloaded and installed Yosemite on a separate partition to play around with it, and then when I decided I liked it, I copied my Mavericks Mac HD onto another partition of the drive as a backup. I then upgraded my main system to Yosemite.
Later on, I decided that I no longer needed the Mac HD clone, since Yosemite is pretty stable at this point, so I removed it; I also resized the Yosemite partition down to 300 GB since I wasn't going to write anything else to it.
The partition map then looked like this:
- Backup: 1.4TB
- Unallocated: 0.3TB
- Yosemite: 0.3TB
- Unallocated: 0.2TB
- Windows Bridge: 0.5TB
That was all fine. However, recently, I installed Windows through Bootcamp on my primary SSD. In Windows' disk management, I tried to remove the Windows Bridge partition and replace it with a 0.7TB NTFS partition. The partition deleted, but the reformat operation failed, so I figured I would boot into OS X, remove the partition, and add a new FAT 0.7 TB partition which could then be reformatted by Windows into NTFS.
I opened up Disk Utility and saw that the Windows Bridge partition was still there according to OS X. So I went ahead and removed it.
And then, bad stuff happened.
The windows partition removed successfully, but the Yosemite partition immediately became unrecognizable by OS X. The files are intact, but OS X sees it as disk1s3, and is unable to read, write, or repair the disk.
The strangest part of it all is that Windows can still read the drive. If I boot into Windows, I can copy anything from the partition, and it works just fine, but boot back into OS X, and the partition is unreadable.
Things I've tried
1. TestDisk and PDisk
I have tried to create my own partition map for the drive using TestDisk to find the partitions and PDisks to create the new partition. TestDisk shows some weird configurations. It appears as though there are two partitions, masquerading as MS Data, assigned to the same set of blocks, with the name Yosemite. That must be causing the problem:
PDisk will not let me open the disk to be rewritten.
pdisk: can't open file '/dev/rdisk1' for writing (Resource busy)
2. Copying all of the files and re-formatting.
Since Windows can read the disk, I figured, why not copy everything from the Yosemite partition onto the Windows ST partition and reformat the broken partition. The only problem with that is that Windows limits path names to 255 bytes, and in OS X, a lot of the files have filenames that are much longer than that. I need all of the files on the drive in order to keep it bootable, so skipping those files that would not copy is out of the question.
So:
Do any of you fine people have any ideas as to how I can fix this partition map and/or get all of my data off of that partition so I can reformat it?
I can definitely go pick up another 3 TB drive to use to copy all of the files off of the existing drive so that the drive can be completely reformatted if you know of a way that I can get all of the files off of the Yosemite partition.
Edit:
> diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *251.0 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_HFS Macintosh HD 200.0 GB disk0s2
3: Apple_Boot Recovery HD 650.0 MB disk0s3
4: Microsoft Basic Data BOOTCAMP 50.1 GB disk0s4
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *3.0 TB disk1
1: EFI EFI 314.6 MB disk1s1
2: Apple_HFS Worth Backup 1.9 TB disk1s2
3: Microsoft Basic Data 300.0 GB disk1s3
4: Microsoft Basic Data WINDOWS ST 510.0 GB disk1s4
> diskutil cs list
No CoreStorage volume groups found
> sudo gpt -r -vvv show -l /dev/disk0
gpt show: /dev/disk0: mediasize=251000193024; sectorsize=512; blocks=490234752
gpt show: /dev/disk0: PMBR at sector 0
gpt show: /dev/disk0: Pri GPT at sector 1
gpt show: /dev/disk0: GPT partition: type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, start=40, size=409600
gpt show: /dev/disk0: GPT partition: type=48465300-0000-11AA-AA11-00306543ECAC, start=409640, size=390624992
gpt show: /dev/disk0: GPT partition: type=426F6F74-0000-11AA-AA11-00306543ECAC, start=391034632, size=1269536
gpt show: /dev/disk0: GPT partition: type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, start=392304640, size=97929216
gpt show: /dev/disk0: Sec GPT at sector 490234751
start size index contents
0 1 PMBR
1 1 Pri GPT header
2 32 Pri GPT table
34 6
40 409600 1 GPT part - "EFI System Partition"
409640 390624992 2 GPT part - "Customer"
391034632 1269536 3 GPT part - "Recovery HD"
392304168 472
392304640 97929216 4 GPT part - "BOOTCAMP"
490233856 863
490234719 32 Sec GPT table
490234751 1 Sec GPT header
> sudo gpt -r -vvv show -l /dev/disk1
gpt show: /dev/disk1: mediasize=3000592977920; sectorsize=4096; blocks=732566645
gpt show: /dev/disk1: Suspicious MBR at sector 0
gpt show: /dev/disk1: MBR part: type=175, start=76806, size=461468854
gpt show: /dev/disk1: MBR part: type=7, start=534820616, size=73242187
gpt show: /dev/disk1: MBR part: type=12, start=608062976, size=124503552
gpt show: /dev/disk1: Pri GPT at sector 1
gpt show: /dev/disk1: GPT partition: type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, start=6, size=76800
gpt show: /dev/disk1: GPT partition: type=48465300-0000-11AA-AA11-00306543ECAC, start=76806, size=461468854
gpt show: /dev/disk1: GPT partition: type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, start=534820616, size=73242187
gpt show: /dev/disk1: GPT partition: type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, start=608062976, size=124503552
gpt show: /dev/disk1: Sec GPT at sector 732566644
start size index contents
0 1 MBR
1 1 Pri GPT header
2 4 Pri GPT table
6 76800 1 GPT part - "EFI System Partition"
76806 461468854 2 GPT part - "Worth Backup"
461545660 73274956
534820616 73242187 3 GPT part - "Yosemite"
608062803 173
608062976 124503552 4 GPT part - "WINDOWS ST"
732566528 112
732566640 4 Sec GPT table
732566644 1 Sec GPT header
> sudo fdisk /dev/disk0
Disk: /dev/disk0 geometry: 30515/255/63 [490234752 sectors]
Signature: 0xAA55
Starting Ending
#: id cyl hd sec - cyl hd sec [ start - size]
------------------------------------------------------------------------
1: EE 1023 254 63 - 1023 254 63 [ 1 - 490234751] <Unknown ID>
2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
3: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
> sudo fdisk /dev/disk1
Disk: /dev/disk1 geometry: 45600/255/63 [732566645 sectors]
Sector size: 4096 bytes
Signature: 0xAA55
Starting Ending
#: id cyl hd sec - cyl hd sec [ start - size]
------------------------------------------------------------------------
1: EE 1023 254 63 - 1023 254 63 [ 1 - 76805] <Unknown ID>
2: AF 1023 254 63 - 1023 254 63 [ 76806 - 461468854] HFS+
3: 07 1023 254 63 - 1023 254 63 [ 534820616 - 73242187] HPFS/QNX/AUX
4: 0C 1023 254 63 - 1023 254 63 [ 608062976 - 124503552] Win95 FAT32L
Best Answer
UPDATE:
There are three partitioning schemes used by both Windows and OS X. The first is MBR, which has been around since the 1980’s. The second is GPT, which is fairly new. The third is a hybrid scheme which combines the first two. OS X’s Disk Utility application allows you to select either MBR or GPT. If MBR is selected, then you get the traditional MBR scheme. On the other hand, if you select GPT, you will get either the GPT or the hybrid MBR/GPT scheme. Normally, the GPT scheme is used, but if one or more partitions have a MS-DOS (FAT) or ExFAT format then the MBR/GPT scheme is employed. If an external drive is hybrid, Windows will see the drive as MBR. If Windows is used to change the partitioning on such as drive, the results are unpredictable. This is why Apple recommends only using MBR to partition an external drive to be used by both OS X and Windows.
I believe your external drive was partitioned as an hybrid drive. The output you posted from the gpt command shows both GPT and MBR partitions.
To review, here is the output you posted from the command
sudo fdisk /dev/disk1. It is the content of the MBR table.We want to remove partition 3 (Yosemite) from the table. When done, the output should appear as shown below.
Start by entering the following command in a Terminal window. The command is interactive. When completed, the Yosemite partition will be removed from the MBR tables. Windows will show the space as unallocated. Other than having a Safari window open to this page, make sure all other windows are closed.
Below is the input to the above command. Note: Your password may be required. I did not include this in the input below.
I thought it might be helpful to include an example. This is what I saw as I entered the above input. Remember, what you will see can differ slightly. Certainly, the integers will be different.
The next set of commands remove the Yosemite partition from the GPT tables, then add the partition back in with the correct UUID. These commands do not alter the content of the partition. Enter the following at the Terminal window.
And you are done.
Let me know how things work out.
You will need to edit your question to post the results. Don't worry about the format, I can clean that up for you. From the Terminal application enter the following commands. Some may require your login password. This is normal.