Hard Drive Partition Showing as "Microsoft Basic Data"

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Level 1

4 points

Hard Drive Partition Showing as "Microsoft Basic Data"

Hi, I have a Mac Pro 2009 with 5 hard drives mounted, one of which (OS) is an SSD connected through PCIe.

The issue is in disk0, partition 3. After a simple restart, the Mac Pro is able to mount and use partition 2 on the same disk (called Caching) but not 3. It didn't even complain about it not being readable.

As you'll see from the terminal output below, I attempted the adjust type option I found from a Google search, but that failed. Prior to this however, it was not even showing in the GUI for Disk Utility... so it did something, but I'm not sure what.

Any suggestions?

Anything I've missed in terms of info, please let me know.

Thanks

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server:~ Admin$ diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *2.0 TB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS Caching 500.0 GB disk0s2

3: Microsoft Basic Data 1.5 TB disk0s3

/dev/disk1 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: FDisk_partition_scheme *2.0 TB disk1

1: Windows_NTFS STOR.E TV+ 2.0 TB disk1s1

/dev/disk2 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk2

1: EFI EFI 209.7 MB disk2s1

2: Apple_HFS CCTV 999.9 GB disk2s2

/dev/disk3 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk3

1: EFI EFI 209.7 MB disk3s1

2: Apple_HFS 1TB Media OS X 999.9 GB disk3s2

/dev/disk4 (external, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *128.0 GB disk4

1: EFI EFI 209.7 MB disk4s1

2: Apple_HFS Macintosh HD 127.2 GB disk4s2

3: Apple_Boot Recovery HD 650.0 MB disk4s3

/dev/disk6 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme +2.0 TB disk6

1: EFI EFI 209.7 MB disk6s1

2: Apple_HFS Time Machine Backups 2.0 TB disk6s2

server:~ Admin$ sudo asr adjust --target /dev/disk0s3 --settype "Apple_HFS"

Password:

asr: Volume adjustment failed: Unknown error: -123

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This is a screenshot after the above command was run.

Mac Pro, OS X El Capitan (10.11.6)

Posted on May 19, 2017 1:27 PM

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Answer 1

akit3492 Author

Level 1

4 points

Jun 16, 2017 4:07 PM in response to akit3492

Just to let anyone know that stumbles upon this, I wasn't able to repair the damage... if there was indeed damage. I searched through the Plex database file and retrieved a list of things that had been stored on the drive. I then formatted the drive and started again, using Mac OS X Extended (Journaled) this time, rather than ExFAT.

Thanks for the time spent by others who replied 🙂

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Answer 2

Jun 16, 2017 4:08 PM in response to akit3492

student of computer science? here is a link to the man pages for MacOS:

https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPag es/

this one for asr:

https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPag es/man8/asr.8.html

this one for diskutil:

https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPag es/man8/diskutil.8.html

.

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Answer 3

May 22, 2017 8:39 AM in response to akit3492

If you are happy to erase the data on the mysterious 1.5TB volume then try the following.

Launch Disk Utility again
On the left select the Untitled volume, this appears to correspond the mysterious Microsoft Basic Data
At the top of the Disk Utility window select Erase to try erasing this volume, hopefully it will then let you chose what format to erase it as via a drop down menu, you want to chose Mac OS Extended Journaled
It should then hopefully also mount

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Answer 4

akit3492 Author

Level 1

4 points

May 22, 2017 8:50 AM in response to John Lockwood

Hi John, thanks for your reply. Sorry, I should have written that I am keen not to lose the data. I have since realised that the partition was originally formatted as exFAT. Obviously this means my attempt with:

sudo asr adjust --target /dev/disk0s3 --settype "Apple_HFS"

was very much the wrong thing to do. I'm hoping it wasn't fatal, however. You wouldn't happen to know, or know somewhere to find out what I should replace Apple_HFS with would you? I would have thought it might have been exFAT, but haven't wanted to try it for risk of making things worse.

I have found this article on my searches:

https://www.reddit.com/r/osx/comments/3y8iak/my_gpt_is_borked/

Which went on to recommend this article:

https://www.reddit.com/r/osx/comments/3hv3kk/update_on_rootless_the_configuratio n_mechanism/

And the other thing I forgot to mention is that I'm a student (Computer Science), and my only current access to the Mac is remote... so I guess I'll need to wait to run the command for when I get home...

But I haven't been able to find out if the asr adjust command supports changing the type of drive to exFAT... any ideas?

Thanks again for your time.

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Answer 5

akit3492 Author

Level 1

4 points

May 22, 2017 9:29 AM in response to Grant Bennet-Alder

Haha! I'm a first year though! That was pretty helpful (despite a little sarcasm I think 😁), thanks! Sooooo, I don't see exFAT in the asr man page... only

--format HFS+ | HFSX

But I see its the man pages for OS X 10.9...

Do you think I messed up trying to run that command? Is there a way of finding out if exFAT is supported in 10.12?

Thanks for your time Grant!

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Answer 6

May 22, 2017 9:40 AM in response to akit3492

No sarcasm was intended. If you are a student of computer science, you are likely a mathematical thinker, and able to read and understand dense technical documents like man pages. In addition, a deeper than usual understanding of these issues is on your direct path forward..

I believe exFAT shows as an option in the diskutil man page, which Is why I included a direct link for that one.

Despite those pages shown as 10.9, they are surprisingly accurate. For up to the minute man pages, you can open a Terminal window, and type

man asr

man diskutil

... but not being a unix-jockey, I find those a little harder to deal with.

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Answer 7

akit3492 Author

Level 1

4 points

Jun 13, 2017 7:40 AM in response to Grant Bennet-Alder

Okay, now I'm home I've disabled csrutil using the recovery partition as described in the reddit link I posted above. I logged back into the Mac, and changed the command to:

sudo asr adjust --target /dev/disk3s3 --settype "ExFAT"

Which showed this error:

asr: Volume adjustment failed: Unknown error: -123

But since a restart, 'diskutil list' is now showing:

/dev/disk3 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *2.0 TB disk3

1: EFI EFI 209.7 MB disk3s1

2: Apple_HFS Caching 500.0 GB disk3s2

3: FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF 1.5 TB disk3s3

Still not sure what it means, and whether its completed screwed, but not ready to give up yet!

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Answer 8

akit3492 Author

Level 1

4 points

May 19, 2017 1:40 PM in response to akit3492

After a restart, the drive still doesn't mount.

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Answer 9

akit3492 Author

Level 1

4 points

May 22, 2017 9:40 AM in response to Grant Bennet-Alder

Hmm, the local man page says the same thing as the one you posted.

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