I'll start off with some information about my USB. I use a SeaGate external hard drive USB with 1 TB. About ~250 gb of it is partitioned and formatted to create a Time-Machine compatible partition. The rest of it is just a normal partition, formatted exFAT, which I use to store data.

I use a 2013 Macbook Air on the latest version of Yosemite.

This drive was working fine until last night, when I attempted to resize it (with iPartition, so I could keep my data) to give the Time Machine Partition just a bit more room. It seems to have worked, but immediately following that OSX gave me a message saying that the larger partition (which I called MISC) was unable to be repaired and should be backed up and reformatted (or something along those lines) ASAP. My Time Machine partition (which I called OSX) seems to be working properly, but I haven't made any new back-ups since then. As far as I can tell, this would not have happened without the iPartition, but I can't be sure.

I really do not want to lose all my data, since I have no way to back up. This is my only large USB and my hard drive is too small to contain the data I had there. So, I am currently trying to use Drive Genius 3 to repair it (only MISC, but I'm fine with it if I can only repair the entire hard drive at once) WITHOUT losing my data. However, it seems I'm not able to repair it because it's set to read only (this was said in an error message given by Drive Genius). I checked the MISC partition using the "Get Info" tab, and it seems that it is set to read only. However, I'm unable to change permissions. I'm pretty sure this is due to whatever caused OSX to give me the message saying that it was unable to be repaired (Disk Utility gives the same message; it also said something like, "You are not able to write to this drive"). It only says something along the lines of, "You may only read this drive." When I get home, I will provide more clear quotes. It doesn't give me options to change the permissions, so I can't just do that.

My questions are: 1. How do I change the permissions on the MISC partition? I'm ok with just forcing this through Terminal if that would work. a. Would Drive Genius actually be able to fix it? Because if not, then there's no point in trying. 2. Are there any other ways to fix this problem without losing all my data? a. Note: I'm fine with losing my OSX partition's data, because I can just make a new back-up (and also that partition works fine and doesn't have an error message).

If I can't do this using Drive Genius, unless you guys give me some other possibility, I'll try to use testdisk 7.0 for the task. I'm not quite familiar with it, so if anyone has experience with it that would be greatly appreciated. Failing that, I'll simply have to do it the regular way that involves losing all my data.

I'm really terrible at a lot of this stuff, so I'll need a lot of handholding unfortunately. Please provide screenshots if possible (and I will do so as well!) for your instructions, especially if it involves Terminal, but mostly for anything. If you know of any programs that might be able to do this, even if they cost money, please link them to me!

Thanks for the help!

  • You never mention buying a new drive to have an actual backup of your data; is that out of the question? Jun 19, 2015 at 1:41
  • 1
    The read-only thing is a safety measure for when the OS detects a corrupted partition, to avoid further corruption. I'm not sure what you can do to salvage your data at the moment... Jun 19, 2015 at 2:24
  • Buying a new drive isn't out of the question, I'd just rather not. If nothing else works, I might just do that, too. Jun 19, 2015 at 17:32

2 Answers 2

  1. You need to buy a new drive onto which you will copy your data from the borked drive. Preferably, this new drive will be a brand other than Seagate, which has the worst failure records in the industry. Once you have safely copied your data to the new drive, you can then begin to worry about how to deal with the Seagate drive.

You can try following these steps:

  1. run the following command in Terminal: diskutil list
  2. Find your disk label in the "NAME" column, and note the identifier all the way on the right (something like "disk#s#")
  3. Now run this command: diskutil unmount MISC
  4. Next run: sudo mkdir /Volumes/MISC && sudo mount -w -t exfat /dev/disk#s# /Volumes/MISC replacing "disk#s#" with your identifier

Try running a repair in Genius 3 again. Hopefully it should work now.

  • gyazo.com/e991798ac97fc6f4abfb1b34ea9cddc2 Is this what Terminal should be giving back after giving it the commands you showed me? Jun 19, 2015 at 17:19
  • Also, it still says the same thing in Drive Genius. However, I once opened the drive in Windows, and it started formatting the drive, but I cancelled it as soon as possible. However, it still seems that it's no longer exfat, it's Windows_NTFS. Should I just change the "exfat" in the last run to Windows_NTFS or should I do something else? Jun 19, 2015 at 17:26
  • Also of note: it says it's Windows_NTFS in Terminal, but according to Disk Utility it's still exFAT. Jun 19, 2015 at 17:41
  • try just the second half sudo mount -w -t exfat /dev/disk#s# /Volumes/MISC again, replacing disk#s# with your identifier Jun 20, 2015 at 2:25

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