External hard drive permissions

Question

Level 1

9 points

External hard drive permissions

Hello all,

I'm fairly new to the Mac world, so please go easy on me. I've been having trouble with an external hard drive I've been sharing between a PC and Mac.

I bought a 1TB Western Digital external hard drive a while back and I partitioned the drive into 2 portions - one that was formatted NTFS and one that was formatted Mac OS Extended (Journaled). I have MacDrive on my PC, which runs Windows 7, so I can read/write on both formats.

The problem arose when a few days ago I found I couldn't write to the Mac formatted portion of the hard drive from my Mac Book Pro. I can still access and write to both portions when I use my PC, so I figure it's something that happened or changed on the Mac. I've searched around a little for help on this problem, but the majority of answers seem to be with changing the permission on the hard drive. The thing is, when I use "Get Info" on the Mac formatted portion, I can't change the permissions (they're all greyed out and unclickable). I'm stumped as I've exhausted my knowledge of the workings of the Mac machine.

Is there anything I can do to fix this?

For reference, my Mac Book Pro is running Mac OS X 10.5.8.

MacBook Pro, Mac OS X (10.5.8)

Posted on Jan 29, 2012 9:09 PM

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Answer 1

JDye

Level 1

5 points

Apr 2, 2012 10:57 AM in response to jinc07

I have the same problem on a external drive that was original from a PC and now it is only read drive, and I want to be able to write on it, without having to reformat or loosing all my files.

from your explanation above I am not sure the mount comand would apply on an external hardrive and if so how would I write the comand without messing up my internal start up drive.

mount -uw /Volumes/"BlackArmor Drive"/

would this be the right comand to write in the Terminal?

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Answer 2

BDAqua

Level 10

238,961 points

Jan 30, 2012 10:13 AM in response to jinc07

Hello, & a warm welcome to the forums & Macdom.

When you do a Get Info on that Mac Partition, can you unlock the lock at the bottom? Is there an ignore Permission on this Volume check box? What are the grayed out permissions staing anyway?

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Answer 3

jinc07 Author

Level 1

9 points

Jan 31, 2012 7:13 PM in response to BDAqua

Hello,

Thanks for the welcome!

When I do a Get Info, I can indeed see a lock at the bottom and some permissions. The lock is unclickable, and the grayed out permissions are as below:

You can only read.

Me - Read & Write

staff - Read & Write

everyone - Read Only

The "Ignore owenership on this Volume" box is checked, but grayed out.

That's pretty much all the information under the "Sharing & Permissions" section.

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Answer 4

BDAqua

Level 10

238,961 points

Jan 31, 2012 7:21 PM in response to jinc07

Open Terminal & paste this in, spaces are important...

chown root /Volumes/

chmod 1777 /Volumes/

then right after the last / of each line, carefully type the name of that external volume, & if it has spaces in it enclose the name in quote marks.

See this User Tip by Niel: I accidentally set a disk's permissions to No Access ...

If the disk in question is your Mac OS X startup disk and your computer stops starting up at the blue screen, restart with the Command and S keys held down, and enter the following commands:

mount -uw /

chown root /

chmod 1775 /

exit

https://discussions.apple.com/docs/DOC-2240

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Answer 5

jinc07 Author

Level 1

9 points

Feb 4, 2012 1:38 PM in response to BDAqua

I've tried your suggestions in Terminal, but I get the following result:

chown: /Volume/volumname: operation not permitted

chmod: /Volume/volumname: read-only file system

Is there a certain way of doing this? I've never used the Terminal before.

Thanks for all your help so far.

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Answer 6

BDAqua

Level 10

238,961 points

Feb 4, 2012 1:51 PM in response to jinc07

Did the mount command work?

And was volume name the Mac Partition?

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Answer 7

jinc07 Author

Level 1

9 points

Feb 4, 2012 2:13 PM in response to BDAqua

Yes, the volumename is the Mac partition. I've actually named it "Mac" to distinguish it from the NTFS Partition.

I haven't tried the mount command because it's not a startup disk and I didn't think it applied to me.

Should I try it?

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Answer 8

BDAqua

Level 10

238,961 points

Feb 4, 2012 2:34 PM in response to jinc07

Yes, it has to be mounted Read & Write, that's why you got...

operation not permitted

read-only file system

You cannot Write anything to a Read Only disk. 🙂

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Answer 9

jinc07 Author

Level 1

9 points

Feb 6, 2012 1:28 AM in response to BDAqua

Hey BDAqua,

I think that's done the trick. I'm not exactly sure of all the inner workings, but I'm now able to both read/write.

Thank you so much for all your help!

Cheers!

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Answer 10

BDAqua

Level 10

238,961 points

Feb 6, 2012 6:26 AM in response to jinc07

Great to hear! 🙂

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Answer 11

BDAqua

Level 10

238,961 points

Apr 2, 2012 11:22 AM in response to JDye

That looks correct, even the 2 spaces, but I'm not sure that'll mount a Fat32 or NTFS drive, NTFS is read only as far as the OS goes anyway, but I don't think it'll hurt to try it.

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Answer 12

Jan 7, 2013 11:20 AM in response to BDAqua

My situation was similar: I had permission to read write to external drive, but not to the password protected diskimage within the drive. Could not change privileges for disk image.

Solution - So I did the unlock on the external drive in (Get Info), and added R W perm for Staff and Everyone - then click the gear icon at the bottom and check "apply privileges to internal volumes" or something like that.

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Answer 13

maryb66

Level 1

4 points

Feb 5, 2014 1:44 AM in response to jinc07

This might help some with similar issues

I had a You can only read, on my external hard drive and no way to unlock it (no lock was visible on get info) after a power failure, ie it wasn't ejected properly. I ejected the drive correct way, that is dragging it to trash, then pulled the USB plug out, waited a few seconds, put it back in again and then it was indexed correctly and I have all my correct permissions.

mb

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Answer 14

Groentas

Level 1

9 points

Apr 2, 2014 12:48 PM in response to jinc07

I have a similar problem with my backup disk from my PC.

I´ve tried to mount it, but with no luck.

christians_macmini:~ CB$mount

....

/dev/disk3s1 on /Volumes/Seagate Backup Plus Drive (ntfs, local, nodev, nosuid, read-only, noowners)

christians_macmini:~ CB$ mount -uw /dev/disk3s1

mount_ntfs: /dev/disk3s1 on /Volumes/Seagate Backup Plus Drive: Operation not permitted

christians_macmini:~ CB$ mount -uw "/Volumes/Seagate Backup Plus Drive"

mount_ntfs: /dev/disk3s1 on /Volumes/Seagate Backup Plus Drive: Operation not permitted

Anybody having any good ideas?

The disk has 4 TB, of which 1 is used.

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Answer 15

Aug 1, 2014 5:41 AM in response to Groentas

Also sharing the PC/OS-X issue. I have an external hard drive that's read-only and when I try to mount it I get this:

mount: unknown special file or file system /Volumes/"volume name"/.

Is it a lost cause at this point? I even tried installing Windows through Parallels just to see if I could more easily change permissions, but no luck.

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