MacOS – Partition sharing – messed up with GPT/MBR

bootcampmacospartitionviwindows

First of all, sorry for any English mistakes or print screen in French… I'm Belgian.

I've had a lot of problems with an iMac 2009 27", mostly with Mac OS. Strangely, Windows (10) works with little to no issue, so I finally decided to run this computer Windows-only. Well… Honestly, I even tried to install Ubuntu, but quickly abandonned.

My abandon of Mac OS led me to a repartitionning of the drive… I kept the Mac OS drive, the bootcamp one, created a shared partition, and (just in case, but I'd like to delete them) two partitions for Linux (OS and Swap).

After that… Windows refused to boot. I managed to find a solution by "repairing" the MBR (or GPT?). Windows boots, but I'm not sure I did everything perfectly.

My big problem now is that I'd like to acess my Share partition. I can, from Mac OS. But from windows, all my other partitions show as "GPT protective partition". And there seems to be nothing I can do.

I'd like to be able to access this Share partition. Even better, I'd like to merge this Share partition with both Linux partition. But I don't want to lose data or screw my MBR/GPT again.

I'm currently on Windows… I'll boot on Mac OS when my computer gets cold (it doesn't boot mac os when warm, that's my main problem), and give you any additional required information.

In advance, thanks for you help!

More informations, that you would probably ask:

iMac-de-Antoine:~ antoine$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            500.0 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data LINUXOS                 32.0 GB    disk0s4
   5:       Microsoft Basic Data SWAP                    5.0 GB     disk0s5
   6:       Microsoft Basic Data DATA                    320.9 GB   disk0s6
   7:       Microsoft Basic Data BOOTCAMP                141.0 GB   disk0s7



iMac-de-Antoine:~ antoine$ sudo gdisk /dev/disk0
Password:
GPT fdisk (gdisk) version 1.0.1

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): i
Partition number (1-7): 7
Partition GUID code: EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 (Microsoft basic data)
Partition unique GUID: A45E8584-415A-4B66-9E37-1FAA60981CC3
First sector: 1678133248 (at 800.2 GiB)
Last sector: 1953523711 (at 931.5 GiB)
Partition size: 275390464 sectors (131.3 GiB)
Attribute flags: 0000000000000000
Partition name: 'BOOTCAMP'



Command (? for help): i  
Partition number (1-7): 6
Partition GUID code: EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 (Microsoft basic data)
Partition unique GUID: BEE4F0DE-2837-4C06-877F-3ADB72B1D173
First sector: 1051031584 (at 501.2 GiB)
Last sector: 1677871103 (at 800.1 GiB)
Partition size: 626839520 sectors (298.9 GiB)
Attribute flags: 0000000000000000
Partition name: 'DOS_FAT_32_Untitled_5'



Command (? for help): p
Disk /dev/disk0: 1953525168 sectors, 931.5 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 00002E14-03EA-0000-EA68-000054300000
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 1953525134
Partitions will be aligned on 8-sector boundaries
Total free space is 787861 sectors (384.7 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1              40          409639   200.0 MiB   EF00  EFI system partition
   2          409640       976972135   465.7 GiB   AF00  Customer
   3       976972136       978241671   619.9 MiB   AB00  Recovery HD
   4       978241672      1040741671   29.8 GiB    0700  DOS_FAT_32_Untitled_4
   5      1041003816      1050769439   4.7 GiB     0700  DOS_FAT_32_Untitled_3
   6      1051031584      1677871103   298.9 GiB   0700  DOS_FAT_32_Untitled_5
   7      1678133248      1953523711   131.3 GiB   0700  BOOTCAMP

More informations:

iMac-de-Antoine:~ antoine$ sudo gpt -r show /dev/disk0
gpt show: /dev/disk0: Suspicious MBR at sector 0
gpt show: error: bogus map
gpt show: unable to open device '/dev/disk0': Undefined error: 0
iMac-de-Antoine:~ antoine$ 


iMac-de-Antoine:~ antoine$ sudo fdisk /dev/disk0
Disk: /dev/disk0    geometry: 121601/255/63 [1953525168 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE    0   0   2 - 1023 254  63 [         1 - 1678133247] <Unknown ID>
*2: 01 1023 254  63 - 1023 254  63 [1678133248 -  274468864] DOS FAT-12  
 3: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 4: 00    0   0   0 -    0   0   0 [         0 -          0] unused

I can clearly understand I messed up… But don't know what to do to repair. =/

NEW, after messing up again with partitions:

iMac-de-Antoine:~ antoine$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            500.0 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data DATA                    358.2 GB   disk0s4
   5:       Microsoft Basic Data BOOTCAMP                141.0 GB   disk0s5


iMac-de-Antoine:~ antoine$ sudo gpt -r show /dev/disk0
Password:
gpt show: /dev/disk0: Suspicious MBR at sector 0
       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   976562496      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
   976972136     1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
   978241672   699629432      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  1677871104      262144         
  1678133248   275390464      5  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  1953523712        1423         
  1953525135          32         Sec GPT table
  1953525167           1         Sec GPT header


iMac-de-Antoine:~ antoine$ sudo fdisk /dev/disk0
Disk: /dev/disk0    geometry: 121601/255/63 [1953525168 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 -  976562496] HFS+        
 3: AB 1023 254  63 - 1023 254  63 [ 976972136 -    1269536] Darwin Boot 
*4: 07 1023 254  63 - 1023 254  63 [ 978241672 -  699629432] HPFS/QNX/AUX

New informations 05-08-16: @david

Disk: /dev/disk0    geometry: 121601/255/63 [1953525168 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE    0   0   2 -   25 127  14 [         1 -     409639] <Unknown ID>
 2: AF   25 127  15 - 1023 254  63 [    409640 -  976562496] HFS+        
 3: 0B 1023 254  63 - 1023 254  63 [ 978241672 -  699629432] Win95 FAT-32
*4: 07 1023 254  63 - 1023 254  63 [1678133248 -  275390464] HPFS/QNX/AUX



Disk: /dev/disk0    geometry: 121601/255/63 [1953525168 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE    0   0   2 -   25 127  14 [         1 -     409639] <Unknown ID>
 2: AF   25 127  15 - 1023 254  63 [    409640 -  976562496] HFS+        
 3: 0B 1023 254  63 - 1023 254  63 [ 978241672 -  699629432] Win95 FAT-32
*4: 07 1023 254  63 - 1023 254  63 [1678133248 -  275390464] HPFS/QNX/AUX
iMac-de-Antoine:~ antoine$ sudo gpt -r show /dev/disk0
gpt show: /dev/disk0: Suspicious MBR at sector 0
       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   976562496      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
   976972136     1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
   978241672   699629432      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  1677871104      262144         
  1678133248   275390464      5  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  1953523712        1423         
  1953525135          32         Sec GPT table
  1953525167           1         Sec GPT header



/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            500.0 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data DATA                    358.2 GB   disk0s4
   5:       Microsoft Basic Data BOOTCAMP                141.0 GB   disk0s5



iMac-de-Antoine:~ antoine$ diskutil list /dev/disk0s4
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            500.0 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data DATA                    358.2 GB   disk0s4
   5:       Microsoft Basic Data BOOTCAMP                141.0 GB   disk0s5

Best Answer

FIX WITH ACCESS TO SHARED PARTITION

To get Windows to boot, you can try entering the following in gdisk from OS X. Before entering the command, you will have to disable System Integrity Protection (SIP). If Windows boots, you will be able to access the new shared partition from Windows. If Windows does not boot, follow the instructions in the section titled "FIX WITHOUT ACCESS TO SHARED PARTITION".

Steelhead:~ davidanderson$ gdisk /dev/disk0
GPT fdisk (gdisk) version 1.0.1

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): r

Recovery/transformation command (? for help): h

WARNING! Hybrid MBRs are flaky and dangerous! If you decide not to use one,
just hit the Enter key at the below prompt and your MBR partition table will
be untouched.

Type from one to three GPT partition numbers, separated by spaces, to be
added to the hybrid MBR, in sequence: 2 4 5
Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): y

Creating entry for GPT partition #2 (MBR partition #2)
Enter an MBR hex code (default AF): af
Set the bootable flag? (Y/N): n

Creating entry for GPT partition #4 (MBR partition #3)
Enter an MBR hex code (default 07): 0b
Set the bootable flag? (Y/N): n

Creating entry for GPT partition #5 (MBR partition #4)
Enter an MBR hex code (default 07): 07
Set the bootable flag? (Y/N): y

Recovery/transformation command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!

Do you want to proceed? (Y/N): y
OK; writing new GUID partition table (GPT) to /dev/disk1.
Warning: Devices opened with shared lock will not have their
partition table automatically reloaded!
Warning: The kernel may continue to use old or deleted partitions.
You should reboot or remove the drive.
The operation has completed successfully.
Steelhead:~ davidanderson$

FIX WITHOUT ACCESS TO SHARED PARTITION

Steelhead:~ davidanderson$ gdisk /dev/disk0
GPT fdisk (gdisk) version 1.0.1

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): r

Recovery/transformation command (? for help): h

WARNING! Hybrid MBRs are flaky and dangerous! If you decide not to use one,
just hit the Enter key at the below prompt and your MBR partition table will
be untouched.

Type from one to three GPT partition numbers, separated by spaces, to be
added to the hybrid MBR, in sequence: 2 3 5
Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): y

Creating entry for GPT partition #2 (MBR partition #2)
Enter an MBR hex code (default AF): af
Set the bootable flag? (Y/N): n

Creating entry for GPT partition #3 (MBR partition #3)
Enter an MBR hex code (default AB): ab
Set the bootable flag? (Y/N): n

Creating entry for GPT partition #5 (MBR partition #4)
Enter an MBR hex code (default 07): 07
Set the bootable flag? (Y/N): y

Recovery/transformation command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!

Do you want to proceed? (Y/N): y
OK; writing new GUID partition table (GPT) to /dev/disk1.
Warning: Devices opened with shared lock will not have their
partition table automatically reloaded!
Warning: The kernel may continue to use old or deleted partitions.
You should reboot or remove the drive.
The operation has completed successfully.
Steelhead:~ davidanderson$

Related Solutions

Windows – Fixing a Windows partition boot using OS X tools

I'll post this as an answer, even though it didn't fix my problem – this was a lost case in the end. Aftermath: I dd'ed a backup of the Windows partition to my OS X partition:

sudo dd bs=512 if=/dev/disk0 of=windows_backup skip=732993496 count=173955112

Now I had a 80 gig hex dump which I could examine safely. I used a hex editor to search for all kinds of metadata:

"NTFS" (encoded in ASCII) which starts a NTFS volume.
"FILE" (encoded in ASCII) which starts a file entry record in the $MFT or master file table in NTFS.
NTFS system file names (like "MFT", tried with little-endian UTF-16 and ASCII)

... and so on. But without success. I was able to find all kinds of data from the dump, but all the metadata, including the boot record (the first sector of the volume), the $Boot file (the first 15 sectors after the boot record), the $MFT file which keeps record of all the files on the file system, were gone.

The thing that baffles me that I couldn't even find $MFTMirr file, which is the backup file of the metadata files and stored halfway of the volume.

I was able to find a backup of the boot sector from its standard location, the last sector of the volume. However, the data was old, from the era before resizing the volume. The boot sector has stored the offset of the $MFT file metadata file, but inspecting the references was moot, there was nothing of value there.

In the end, I concluded that the volume was totally borked. The moral of the story? Hybrid Master Boot Record is evil. Also, it seems that the program that resized the volume did a subpar job, failing to update some of the metadata.

I think I messed up the Fusion Drive on the 1TB iMac (with BootCamp)

Theoretically everything is fine with your Fusion Drive. Fusion Drives look like this. Disk0 is your SSD with 121 GB and disk1 is your HDD with ~1 TB (~1.121 TB summed up).

The larger parts of your SSD (disk0s2) and your HDD (disk1s2) are pooled to a CoreStorage LVG (Fusion Drive: disk3) with a size of 967.8 GB. The rest is reserved for EFIs, a Recovery HD (alltogether ~1.3 GB) and your old Windows partition - now probably free space (~152 GB).

The logical volume 'Macintosh HD' (967.8 GB) spans disk0s2 and disk1s2. This is the first 'Macintosh HD' in picture 1. The volume 'Macintosh HD' - it's the one visible on the desktop - should ideally also have about 967.8 GB. This is the second 'Macintosh HD' in picture 1.
In fact it has only 852.67 GB (see picture 3).

In the second picture the logical volume 'Macintosh HD' is the first listed in black, the volume 'Macintosh HD' is the second listed in black, the other two 'Macintosh HD's listed in grey are the parts of your SSD and HDD dedicated to the logical volume 'Macintosh HD'.

In my opinion something went wrong after deleting various partitions with the Bootcamp Assistant/Disk Utility or in Windows.

Preparation:

Detach any external drive (especially your external Time Machine backup drive)
Restart to Internet Recovery Mode by pressing alt cmd R at startup.
The prerequisites are the latest firmware update installed, either ethernet or WLAN (WPA/WPA2) and a router with DHCP activated.
On a 50 Mbps-line it takes about 4 min (presenting a small animated globe) to boot into a recovery netboot image which usually is loaded from an apple/akamai server.

I recommend ethernet because it's more reliable. If you are restricted to WIFI and the boot process fails, just restart your Mac until you succeed booting.

Alternatively you may start from a bootable installer thumb drive (preferably Mavericks or Yosemite) or a thumb drive containing a full system (preferably Mavericks or Yosemite).

Now you may either repair CoreStorage or rebuild your Fusion Drive:

'Repair CoreStorage' (not recommended):

First i would try to check the volume 'Macintosh HD' with Disk Utility. If the volume is corrupted consider a reinstall of Mac OS X.
If the volume is ok quit Disk Utility
Open Terminal and enter diskutil unmountDisk /dev/LVIdentifier and both diskutil unmountDisk /dev/DiskContainingApple_CoreStorageIdentifier
In your case: first diskutil unmountDisk /dev/disk3 then diskutil unmountDisk /dev/disk0 and diskutil unmountDisk /dev/disk1
remove the EFI NO NAME partition with gpt remove -i IndexNumberOfEFINoName DiskIdentifier:
gpt remove -i 4 disk1
Remount the CoreStorage disks and then the Logical Volume:
In your case: first diskutil mountDisk /dev/disk0 and diskutil mountDisk /dev/disk1 and then diskutil mount /dev/disk3.

enter gpt -r -vvv show /dev/diskIdentfierOfApple_CoreStorage to get infos of your HDD CoreStorage disk.
In your case: gpt -r -vvv show /dev/disk1
It should look like this:

-bash-3.2# gpt -r -vvv show /dev/disk1
gpt show: /dev/disk1: mediasize=1000204886016; sectorsize=512;         blocks=1953525168
gpt show: /dev/disk1: PMBR at sector 0
gpt show: /dev/disk1: Pri GPT at sector 1
gpt show: /dev/disk1: GPT partition: type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, start=40, size=409600
gpt show: /dev/disk1: GPT partition: type=53746F72-6167-11AA-AA11-00306543ECAC, start=409640, size=1671210848
gpt show: /dev/disk1: GPT partition: type=426F6F74-0000-11AA-AA11-00306543ECAC, start=1671620488, size=1269760
gpt show: /dev/disk1: Sec GPT at sector 1953525167                               
     start          size  index contents                                        
         0             1        PMBR                                            
         1             1        Pri GPT header                                  
         2            32        Pri GPT table                                   
        34             6
        40        409600      1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
    409640    1671210848      2 GPT part - 53746F72-6167-11AA-AA11-00306543ECAC
1671620488       1269760      3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
1672890248     280634887
1953525135            32        Sec GPT table
1953525167             1        Sec GPT header

The free space on your HDD has 280634887 blocks. Please calculate the biggest block number dividable through 8. That's 280634880 blocks (á 512 bytes) which equals 143685058560 B or ~143.7 GB. Add the size of your HDD CoreStorage Physical Volume (852666400768 B) The result is 143685058560 B + 852666400768 B = 996351459328 B
Resize your HDD CoreStorage physical volume with diskutil cs resizeDisk HDDPVUUID newsize
In your case: diskutil cs resizeDisk 93892BE8-2B7F-4ABD-A4C3-984495DCD98D 996351459328b
Calculate the maximal size of your CoreStorage Logical Volume in diskutil cs list: (size disk0s2) + (size disk1s2) In your case that's 120988852224 B + 996351459328 B = 1117340311552 B. That should be the size of your refreshed Logical Volume Group.
Resize your Logical Volume with diskutil cs resizeVolume LVUUID LVGSize-128 MB In your case that's diskutil cs resizeVolume D237FFDC-7DA4-41D7-AC13-4CC7E5E8C0A0 1117212311552b. If you get an error (There is not enough free space...) choose a smaller size like 1117148311552b.
Quit Terminal and open Disk Utility.
Check your expanded CoreStorage Volume for errors.
Quit Disk Utility, choose your CS volume as startup disk and restart your Mac

'Rebuild Fusion Drive' (recommended if you have a Time Machine backup)

Booted to Internet Recovery Mode open Utilities → Terminal in the menubar and enter:
diskutil cs list to get the CoreStorage listing.
Copy the Logical Volume UUID, it's the fifth listed.
Now delete the Logical Volume with diskutil cs deleteVolume LVUUID.
In your case: diskutil cs deleteVolume D237FFDC-7DA4-41D7-AC13-4CC7E5E8C0A0.
Copy the Logical Volume Group UUID, it's the first listed in the listing of diskutil cs list.
Then delete the Logical Volume Group with diskutil cs delete LVGUUID.
In your case: diskutil cs delete 1EFE58BC-3613-44C4-86EE-D816F3B66E3E
Enter exit and quit 'Terminal'
Open 'Disk Utility'. Enter 'Ignore' if you are asked to fix the drives.
Choose your SSD and partition it: 1 Partition Mac OS X Extended (Journaled), hit the Options button and choose GUID Partiton table and hit OK and Apply.
Please check that the size is ~121 GB

Example:
Choose your HDD and partition it: 1 Partition Mac OS X Extended (Journaled), hit the Options button and choose GUID Partiton table and hit OK and Apply.
Please check that the size is ~1 TB

Example:
Quit Disk Utility and open Terminal
Enter diskutil list

Example (your disk identifiers and sizes are different of course: Your volume SSD probably has the Identifier disk0s2 and the size 121 GB and your volume HDD probably has the Identifier disk1s2 and the size 1.0 TB):
Enter diskutil cs create "Name" IdentifierSSD IdentifierHDD
In your case probably diskutil cs create "Macintosh HD" disk0s2 disk1s2.

Copy the resulting LVGUUID

Example:
Enter diskutil cs CreateVolume LVGUUID jhfs+ "Macintosh HD" 100%.

Example:
Enter diskutil cs list
Check the size of your Logical Volume. It should have the size ~1.121 TB

Example:
Quit Terminal
Open 'Disk Utility' and check your newly created volume for errors
Quit 'Disk Utility'
Attach your external Time Machine backup drive or check this answer if you use NAS or another network share.
Open 'Restore from Time Machine Backup'
Choose the appropriate Time Machine backup and restore your system
Reboot to your restored system.
Unmount and detach your Time Machine backup drive
Open 'Terminal' and enter 'diskutil list'
Check if your 'Recovery HD' is listed.
If your 'Recovery HD' is missing, usually reinstalling your current system with the latest available system installer (e.g. 'Install OS X Mavericks (10.9.5)' if Mavericks is currently installed) will recreate it without loosing any data. AFAIK Recovery Partition Creator 3.8 will NOT create a Recovery HD on CoreStorage volumes.
After reinstalling the system with the latest available system installer open App Store and install the latest security fixes.