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Running a Mac Pro 2013 with macOS Catalina. Looking to change the GUID type from FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF to 7C3457EF-0000-11AA-AA11-00306543ECAC. I've been browsing through various previous posts about this issue but have not found the solution that I need yet or anyone having the same problem.

After running the diskutil umountDisk disk0 and gpt remove -i 2 disk0 commands, I went to add the disk back using this command gpt add -i 2 -b 409640 -s 768896136 -t 53746F72-6167-11AA-AA11-00306543ECAC disk0 and got this error message gpt add: unable to open device 'disk0': Resource busy. I've noticed as well that after running gpt -r show disk0, index 2 has switched from FFF... to MBR part 218 and disk0s2 is no longer listed when calling diskutil list. I can't seem to figure out where to go from here.

Here is what I have done so far

-bash-3.2# diskutil list
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2: FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF               393.7 GB   disk0s2
   3:       Microsoft Basic Data BOOTCAMP                56.1 GB    disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     Apple_partition_scheme                         *1.3 GB    disk1
   1:        Apple_partition_map                         30.7 KB    disk1s1
   2:                  Apple_HFS OS X Base System        1.3 GB     disk1s2
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk2
/dev/disk3
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk3
/dev/disk4
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk4
/dev/disk5
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk5
/dev/disk6
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk6
/dev/disk7
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *6.3   MB  disk7
/dev/disk8
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *2.1   MB  disk8
/dev/disk9
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *1.0   MB  disk9
/dev/disk10
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk10
/dev/disk11
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk11
/dev/disk12
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *1.0   MB  disk12
-bash-3.2# gpt -r show disk0
gpt show: 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  768896136      2  GPT part - FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF
  769305776   98292560         
  867598336  109506560      3  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  977104896        131         
  977105027         32         Sec GPT table
  977105029          1         Sec GPT header
-bash-3.2# diskutil unmountDisk disk0
Unmount of all volumes on disk0 was successful
-bash-3.2# gpt remove -i 2 disk0
gpt remove: disk0: Suspicious MBR at sector 0
disk0s2 removed
-bash-3.2# gpt add -i 2 -b 409640 -s 768896136 -t 7C3457EF-0000-11AA-AA11-00306543ECAC  disk0
gpt add: unable to open device `disk0`: Resource busy
-bash-3.2# diskutil list
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:       Microsoft Basic Data BOOTCAMP                56.1 GB    disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     Apple_partition_scheme                         *1.3 GB    disk1
   1:        Apple_partition_map                         30.7 KB    disk1s1
   2:                  Apple_HFS OS X Base System        1.3 GB     disk1s2
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk2
/dev/disk3
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk3
/dev/disk4
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk4
/dev/disk5
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk5
/dev/disk6
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk6
/dev/disk7
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *6.3   MB  disk7
/dev/disk8
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *2.1   MB  disk8
/dev/disk9
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *1.0   MB  disk9
/dev/disk10
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk10
/dev/disk11
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *524.3 KB  disk11
/dev/disk12
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled                *1.0   MB  disk12
-bash-3.2# gpt -r show disk0
gpt show: 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  768896136      2  MBR part 218
  769305776   98292560         
  867598336  109506560      3  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  977104896        131         
  977105027         32         Sec GPT table
  977105029          1         Sec GPT header

Not sure where to go from this point and appreciate any help with getting this solved

IconDaemon
  • 19,234
cheoso
  • 23
  • You received the error message gpt add: unable to open device 'disk0': Resource busy, because you did not enter the command diskutil umountDisk disk0 before entering the command gpt add -i 2 -b 409640 -s 768896136 -t 53746F72-6167-11AA-AA11-00306543ECAC disk0. – David Anderson Feb 12 '24 at 02:12
  • I should also point out that 53746F72-6167-11AA-AA11-00306543ECAC is for Core Storage and I believe Catalina cannot be installed on Core Storage volumes. – David Anderson Feb 12 '24 at 02:21
  • The 3rd command I made was diskutil unmountDisk disk0. Made that call right after the gpt -r show disk0 command – cheoso Feb 12 '24 at 02:31
  • I have made the assumption that disk0s3 mounted after you entered gpt remove -i 2 disk0. – David Anderson Feb 12 '24 at 02:38
  • What do you think would be the best command to try in this case then? should I do after gpt remove -i 3 disk0 or would it be something else? – cheoso Feb 12 '24 at 03:04

1 Answers1

0

The commands below were derived from the answers to the question OS volume shows as type 'FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF'.

fdisk -d /dev/disk0 > /var/tmp/mbr.txt
fdisk -f /dev/zero -e /dev/disk0
setpid 2
0
quit
yes
diskutil unmountDisk disk0
gpt add -i 2 -b 409640 -s 768896136 -t 7C3457EF-0000-11AA-AA11-00306543ECAC disk0
diskutil unmountdisk disk0
fdisk -f /dev/zero -r -y /dev/disk0 < /var/tmp/mbr.txt
rm /var/tmp/mbr.txt
David Anderson
  • 40,244
  • appreciate it! this solved it for me – cheoso Feb 12 '24 at 04:20
  • Thanks. I suppose since this really is a duplicate question, I should make it official. – David Anderson Feb 12 '24 at 04:25
  • 1
    Go for it! I was looking at the post you had mentioned earlier, however did not go far enough down to see where you had mentioned the final steps that you put into this post. apologize about that – cheoso Feb 12 '24 at 05:53
  • Hi I'm super sorry to bring back this thread, but I have one more question if you don't mind me asking I'm missing around 50 GB on my SSD. If you look, you see that after calling diskutil list, I have storage of 500GB. 394 GB is listed as the space for disk0s2 (macOS) and 56 GB is listed for disk0s3 (Windows). I originally had Linux installed as well and after trying to erase the Linux partition and merging it with macOS, I got the initial problem that you helped fix. Do you have any insight into why I might be missing so much space? – cheoso Mar 02 '24 at 06:41
  • I found a reply you made to use sudo diskutil apfs resizeContainer disk0s2 0. appreciate that a lot. it reformatted my drive with "FFFFFF..." however, so I had to go through these steps again. Now when I boot the computer, macOS is not listed. I noticed that when I run fdisk /dev/disk0, I get <Unknown ID> for the start number associated with macOS. So sorry to bother but I appreciate any help you're willing to give – cheoso Mar 02 '24 at 07:33