Mac OS X: partition disappeared but visible in TestDisk

How to use TestDisk to recover lost partition
Post Reply
Message
Author
msephton
Posts: 2
Joined: 24 Aug 2015, 18:42

Mac OS X: partition disappeared but visible in TestDisk

#1 Post by msephton » 24 Aug 2015, 19:26

Mac OS X

I have an external Thunderbolt drive (LaCie Rugged 1GB)

It containing EFI GPT partition map with 2 partitions.

Code: Select all

     Partition                  Start        End    Size in sectors
> 1 P EFI System                    40     409639     409600
  2 P Mac HFS                   409640 1758612767 1758203128
  3 P MS Data               1758875648 1953523711  194648064
However, the MS Data (exFAT) partition has disappeared in Mac OS X (Finder, Disk Utility) but is visible in TestDisk (see above).

What steps should I take to make the partition visible once more to Mac OS X?

Thanks!
Last edited by msephton on 25 Aug 2015, 11:43, edited 1 time in total.

Sponsored links

msephton
Posts: 2
Joined: 24 Aug 2015, 18:42

Re: Mac OS X: partition disappeared but visible in TestDisk

#2 Post by msephton » 25 Aug 2015, 08:28

So I figured this out.

First step was trying to mount the drive from Terminal. Output said that one partition failed to mount because it is corrupted. Progress! The system knows about the partition and what is wrong.

Googling this error led to the following page:
http://craigsmith.id.au/2014/07/06/repa ... partition/

Code: Select all

fsck_exfat -d disk0s4
Scans partition disk0s4 (change for your specific partition) in some way, all file names whizzing by on screen and then a summary. Interestingly, the output didn't seem to show that any changes had been made!

and then it asks
Main boot region needs to be updated. Yes/No?
From here I could use disk utility to do First Aid on the drive and it reappeared on my desktop.

Hopefully that's useful for somebody else!

Post Reply

Who is online

Users browsing this forum: No registered users and 0 guests