Q: windows 8 does not recognise Macintosh HD, No drive Letter

Your little code allows me to access OS X part files and folders while I am in Windows 8.1 part. Awesome! You have saved my life dude!

Guys!

Actually, you can REVERT the "corestorage" volume back to HFS+. Even on new macbooks.

I bought a brand new retina mac with Yosemite preinstalled (not upgrade) and was abel to revert.

Run

diskutil cs list

And check the last "Logical volume" in the output. If it says "Revertible YES" this means you're saved. Again, it says so even on brand new Yosemite machines from Apple Store (bought mine this April, 2 weeks ago)

UPDATE: Oh, I see "creativeprogramming" has already covered this. Follow his answer.

Terrific post, sorry to hear about your i7 turbo issues. I'm hoping you can help me with terminal which I know little about. I've only ever executed a few baby-step terminal moves, and in my mind's eye I'm imagining I could brick my machine with an error. So far I've done everything on your list except the final move - the # 6) diskutil corestorage revert <UUID>. I located my Logical Volume "UUID" (that string of 32 or so letters & numbers to the right, I'm guessing...) and found the 'Revertible:Yes' text. In the # 6 move I suspect I do NOT include the brackets <> right? Finally - is this mod reversible? Do we lose any functionality from going back to HFS+ from Core Storage - are there any disadvantages? I not really all that concerned - mostly curious. Thanks in advance for your remarks - Cheers

You do not use "<>". These are used to indicate a user-specific item to be used. If it is revertible, you can. It is not always the case that CS volume is revertible.

It is a reversible modification. You can use diskutil cs create to go back to a CS volume. CS has advantages, where you can add disks and remove disks on the fly. HFS+ can be read on the Windows side, but I expect the new OS to provide a CS read-only driver with W10 release.

Problem.

It took me a while, but I finally pulled the trigger on this move and now I'm locked out of my Windows side. If I restart from OS X side holding down alt/option key I can see both drive icons BUT the Windows one is now called EFI boot and clicking it only brings up the Restore interface.

Any chance you can help me fix or undo this?

Right before I rebooted I copied the Terminal text:

MacBook-Pro:~ LDDS$ sudo su

Password:

sh-3.2# diskutil corestorage list

CoreStorage logical volume groups (1 found)

|

+-- Logical Volume Group BC92620B-F228-41B5-A6A4-A053945A3C24

    =========================================================

    Name:         Untitled

    Status:       Online

    Size:         374418034688 B (374.4 GB)

    Free Space:   18903040 B (18.9 MB)

    |

    +-< Physical Volume 2B580042-A6BE-4731-9D96-746227AAEE7D

    |   ----------------------------------------------------

    |   Index:    0

    |   Disk:     disk0s2

    |   Status:   Online

    |   Size:     374418034688 B (374.4 GB)

    |

    +-> Logical Volume Family 1E6CBC4E-6AD6-49B6-A1EB-1CD7AEE18E6A

        ----------------------------------------------------------

        Encryption Status:       Unlocked

        Encryption Type:         None

        Conversion Status:       NoConversion

        Conversion Direction:    -none-

        Has Encrypted Extents:   No

        Fully Secure:            No

        Passphrase Required:     No

        |

        +-> Logical Volume 2940A4A5-9AB6-4D86-8E35-E96831159A9A

            ---------------------------------------------------

            Disk:                  disk1

            Status:                Online

            Size (Total):          374046810112 B (374.0 GB)

            Conversion Progress:   -none-

            Revertible:            Yes (no decryption required)

            LV Name:               Untitled

            Volume Name:           Untitled

            Content Hint:          Apple_HFS

sh-3.2# diskutil corestorage revert 2940A4A5-9AB6-4D86-8E35-E96831159A9A

Started CoreStorage operation on disk1 Untitled

Switching partition from Core Storage type to original type

Reclaiming space formerly used by Core Storage metadata

Even though the disk is now fully reverted, you should reboot soon to re-mount your reverted disk from the actual original partition

Removing Physical Volume

Destroying Logical Volume Group

Remounting former Physical Volume as normal disk

Core Storage LV UUID: 2940A4A5-9AB6-4D86-8E35-E96831159A9A

Core Storage disk: disk0s2

Finished CoreStorage operation on disk1 Untitled

sh-3.2#

Can you post the output of

diskutil list

sudo gpt -vv -r show /dev/disk0

sudo fdisk /dev/disk0

So kind of you to assist.....

Last login: Mon Aug 24 18:35:52 on console

Ls-MacBook-Pro:~ LDDS$ diskutil list

/dev/disk0

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *500.3 GB   disk0

   1:                        EFI EFI                     209.7 MB   disk0s1

   2:                  Apple_HFS Untitled                374.4 GB   disk0s2

   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

   4:       Microsoft Basic Data Windows                 125.0 GB   disk0s4

Ls-MacBook-Pro:~ LDDS$ sudo gpt -vv -r show /dev/disk0

Password:

gpt show: /dev/disk0: mediasize=500277790720; sectorsize=512; blocks=977105060

gpt show: /dev/disk0: Suspicious MBR at sector 0

gpt show: /dev/disk0: Pri GPT at sector 1

gpt show: /dev/disk0: Sec GPT at sector 977105059

      start       size  index  contents

          0          1         MBR

          1          1         Pri GPT header

          2         32         Pri GPT table

         34          6        

         40     409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

     409640  731285224      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC

  731694864    1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

  732964400        464        

  732964864  244140032      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

  977104896        131        

  977105027         32         Sec GPT table

  977105059          1         Sec GPT header

Ls-MacBook-Pro:~ LDDS$ sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 60821/255/63 [977105060 sectors]

Signature: 0xAA55

         Starting       Ending

#: id  cyl  hd sec -  cyl  hd sec [     start -       size]

------------------------------------------------------------------------

1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>

2: AF 1023 254  63 - 1023 254  63 [    409640 -  731285224] HFS+       

3: AB 1023 254  63 - 1023 254  63 [ 731694864 -    1269536] Darwin Boot

4: 0C 1023 254  63 - 1023 254  63 [ 732964864 -  244140032] Win95 FAT32L

Ls-MacBook-Pro:~ LDDS$

Let us try the simple fix first on the MBR. Please ignore i386 MBR error message, but not any other messages.

sudo fdisk -e /dev/disk0

p

setpid 4

07

flag 4

p

w

y

Reboot into OS X and try to switch to Windows using System Preferences -> Startup Disk -> select Bootcamp -> Restart.

Once in Windows, run Disk Management and post the layout of Disk 0.

Last login: Tue Aug 25 07:06:21 on console

Lionels-MacBook-Pro:~ LDDS$ sudo fdisk -e /dev/disk0

Password:

fdisk: could not open MBR file /usr/standalone/i386/boot0: No such file or directory

Enter 'help' for information

fdisk: 1> p

Disk: /dev/disk0 geometry: 60821/255/63 [977105060 sectors]

Offset: 0 Signature: 0xAA55

         Starting       Ending

#: id  cyl  hd sec -  cyl  hd sec [     start -       size]

------------------------------------------------------------------------

1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>

2: AF 1023 254  63 - 1023 254  63 [    409640 -  686363352] HFS+       

3: AB 1023 254  63 - 1023 254  63 [ 686772992 -    1269536] Darwin Boot

*4: 07 1023 254  63 - 1023 254  63 [ 688044032 -  289060864] HPFS/QNX/AUX

fdisk: 1> setpid 4

         Starting       Ending

#: id  cyl  hd sec -  cyl  hd sec [     start -       size]

------------------------------------------------------------------------

*4: 07 1023 254  63 - 1023 254  63 [ 688044032 -  289060864] HPFS/QNX/AUX

Partition id ('0' to disable)  [0 - FF]: [7] (? for help) 07

fdisk: 1> flag 4

Partition 4 marked active.

fdisk:*1> p

Disk: /dev/disk0 geometry: 60821/255/63 [977105060 sectors]

Offset: 0 Signature: 0xAA55

         Starting       Ending

#: id  cyl  hd sec -  cyl  hd sec [     start -       size]

------------------------------------------------------------------------

1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>

2: AF 1023 254  63 - 1023 254  63 [    409640 -  686363352] HFS+       

3: AB 1023 254  63 - 1023 254  63 [ 686772992 -    1269536] Darwin Boot

*4: 07 1023 254  63 - 1023 254  63 [ 688044032 -  289060864] HPFS/QNX/AUX

fdisk:*1> w

Device could not be accessed exclusively.

A reboot will be needed for changes to take effect. OK? [n] y

Writing MBR at offset 0.

fdisk: 1>

Sorry - I have to interrupt with a question - I am inclined to wipe the drive (at this point it isn't a big deal as I've saved everything) but I don't know if wiping the drive restores the changes made via Terminal. Does a wipe & clean install restore everything to 'factory' settings?

Why are

Ls-MacBook-Pro:~ LDDS$ sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 60821/255/63 [977105060 sectors]

Signature: 0xAA55

         Starting       Ending

#: id  cyl  hd sec -  cyl  hd sec [     start -       size]

------------------------------------------------------------------------

1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>

2: AF 1023 254  63 - 1023 254  63 [    409640 -  731285224] HFS+      

3: AB 1023 254  63 - 1023 254  63 [ 731694864 -    1269536] Darwin Boot

4: 0C 1023 254  63 - 1023 254  63 [ 732964864 -  244140032] Win95 FAT32L

and (this is from the 'p' command before the flag command was executed)

Disk: /dev/disk0 geometry: 60821/255/63 [977105060 sectors]

Offset: 0 Signature: 0xAA55

         Starting       Ending

#: id  cyl  hd sec -  cyl  hd sec [     start -       size]

------------------------------------------------------------------------

1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>

2: AF 1023 254  63 - 1023 254  63 [    409640 -  686363352] HFS+      

3: AB 1023 254  63 - 1023 254  63 [ 686772992 -    1269536] Darwin Boot

*4: 07 1023 254  63 - 1023 254  63 [ 688044032 -  289060864] HPFS/QNX/AUX

different?

1. Do you have two disks with Bootcamp with different layouts?

2. Are you trying to clone from one to another?

Loner T - I want to thank you for your patient assistance. In regards to the above [minus a long story] I deleted the partition. Later on, I accessed Apple Internet Recovery, used Disk Utility to wipe the drive of Yosemite, and did a Factory install of Mavericks. I know if I upgrade to Yosemite FROM Mavericks I will be able to access OS X from Windows. My mistake was in performing a clean install of Yosemite [hoping to clear up the Apple Mail issues - my goodness, Yosemite causes glitches!]. Once I had a clean install of Mavericks I was hoping that the Apple BC Assistant would create an "older" Windows 7 user-friendly install download. I was REALLY thrown Apple's dumping of W7 support [in favour of W8 & W10]. But no such luck. Using your methods posted elsewhere I found my way through to a healthy W7 install. What Apple has failed to consider is that many boot camp users [such as myself] only own an upgrade license to Windows 8. Windows 7 is still a MUST. Even if only for the sake of upgrading to a free copy of Windows 10.

Yosemite was a lot of fun and it's very colourful, but I think I will stick to the stability of Mavericks for a while - and Windows 7. Let me know if there's anything you wanted to know. Cheers

Very to see you at least arrived at a 'safe' place, despite the bumps. Please make back ups of your OSes to be better prepared for future glitches.

Hello Creative,

I have a Mac 27 retina with Yosemite preinstalled and now updated to El Capitan.

I made a bootcamp installing Windows 10, but I have the same problem: I'm not able to see Macintosh HD from Win10.

This is my diskutil cs list:

Last login: Wed Dec 23 21:09:59 on ttys000

iMac-di-MAURO:~ maurolazzerini$ diskutil cs list

CoreStorage logical volume groups (1 found)

|

+-- Logical Volume Group 6DBB0B24-62FC-4081-BC93-F65733288A33

    =========================================================

    Name:         Internal Drive

    Status:       Online

    Size:         772855619584 B (772.9 GB)

    Free Space:   442368 B (442.4 KB)

    |

    +-< Physical Volume 21559397-143D-4CF3-B3A3-CA6FF9D800D6

    |   ----------------------------------------------------

    |   Index:    0

    |   Disk:     disk0s2

    |   Status:   Online

    |   Size:     120988852224 B (121.0 GB)

    |

    +-< Physical Volume 30B046F6-FFFA-49C9-A0EE-613D10B947CE

    |   ----------------------------------------------------

    |   Index:    1

    |   Disk:     disk1s2

    |   Status:   Online

    |   Size:     651866767360 B (651.9 GB)

    |

    +-> Logical Volume Family CB39499F-AC7A-472E-9A4C-D8DC517FCE48

        ----------------------------------------------------------

        Encryption Type:         None

        |

        +-> Logical Volume F9080A3B-8DB3-4D4A-A9C7-BFE2CD77F408

            ---------------------------------------------------

            Disk:                  disk2

            Status:                Online

            Size (Total):          766999920640 B (767.0 GB)

            Revertible:            No

            LV Name:               Macintosh HD

            Volume Name:           Macintosh HD

            Content Hint:          Apple_HFS

            LVG Type:              Fusion, Sparse

As you can see, it says revertible no

Can you give me advice please?

Thanks

A Fusion drive cannot be reverted. You will not be able to see OSX parts in Windows.