external hard drive went read only

That explains it, OS X doesn't support writes to NTFS, that's a proprietary format and any previous hacks were that hacks and Apple disabled it.

Connect the drive to a PC, offload the data then use a PC to format it exFAT and then you can use it on either.

If it's a XP box, there is a free exFAt download from Microsoft.

You can buy software for the Mac to read/Write the NTFS format, but then you have to pay and upgrade and just to have it break sometime when you least expect it.

https://discussions.apple.com/community/notebooks/macbook_pro?view=documents

BookX wrote:

I sugest you read and understand what this represents at their site:

"reformatting to HFS+ required to use backup software for Mac or Time Machine® software"

I referred you to

<http://www.seagate.com/www/en-us/products/external/external-hard-drive/mac-deskt op-hard-drive>

which is a Seagate hard drive. The string "HFS+" appears on this page only twice. Here:

• Comes formatted for Mac computers, but works on PC computers too
• Makes it easy to read, write and share files interchangeably between both Mac and PC computers with the included downloadable HFS+ driver for PCs

and here

*HFS+ driver for PC operability available by download

Compatibility may vary depending on user's hardware configuration

If you have any further nuggets of wisdom or misquotes to contribute, I suggest taking it up with Seagate.

If you never plugged it into a Windows PC thenn how did you load any files on it as Mac OS X can not write to NTFS formatted drives.

That is why it is Read Only because OS X can read NTFS but can't writer to it.

Shootist007 wrote:

That is why it is Read Only because OS X can read NTFS but can't writer to it.

Possibly, but there are instances where error or corruption on a non-NTFS drive caused Mac OS X to treat it as NTFS. It the OP did indeed write to it with a Mac, this may be the case.

Okay... If you are going to use your portable HDD only with OS X systems, then copy the files from it to a safe place and format the HDD with the native Mac OS Extended (Journaled) file format, then move files back to it.

NTFS (New Technology File System) is the standard file system of Windows NT and OS X systems can only write and copy to this kind of format.

DanDoor wrote:

on the external hard drives box it says that it's compatible with mac and as i said, it was working fine with my mac, i just dont know how the hard drives format changed randomly.

It didn't. The notice about NTFS is bogus. Sometimes, disk corruption fools the Finder into believing that the file system is NTFS (for which Mac OS X does not have native write support); this is probably your case. The only solution is to reformat the drive (which will destroy all data presently on it). Back up all you can from it first. IIRC, your Seagate FreeAgent GoFlex Desk is self-powered (ie, it has its own power supply). If it is bus-powered, you should be aware that a common issue in MBPs is that they don't provide a lot of power on the USB bus, so a possible cause of disk corruption was inadequate power. You should get a power supply for it. If it already has a power supply, then the cause of corruption is something else.

On a second note, all Seagate hdd are NTFS formatted by default from manufacturer. In other words the hdd is plug and play ready for Windows OS. However, If you intend to use it on Mac, then you need to format it with Mac OS Extended (Journaled) to be compatible with OS X.

There is no data corruption at all, just limited usage on NTFS partition until you make it compatible for OS X.

BookX wrote:

all Seagate hdd are NTFS formatted by default from manufacturer.

I suggest verifying your information prior to posting. This drive

<http://www.seagate.com/www/en-us/products/external/external-hard-drive/mac-deskt op-hard-drive>

is a Seagate drive, and it is not formatted as NTFS. If you consult its data sheet, you'll find it's formatted as HFS+, and compatibility with Windows is provided by a suitable driver, available for download from Seagate.

If you need further information about Seagate drives, I suggest consulting Seagate directly, or, at least, reading some of the data sheets and tech papers provided by Seagate free of charge.

I sugest you read and understand what this represents at their site:

"reformatting to HFS+ required to use backup software for Mac or Time Machine® software"

fane_j wrote:

If it is bus-powered, you should be aware that a common issue in MBPs is that they don't provide a lot of power on the USB bus, so a possible cause of disk corruption was inadequate power.

The BUS does not supply power to the USB port. If there's not enough power at USB for HDD then it won't initialize, not even spin to begin with.

You keep posting a link that doesn't mean anything in terms of technical data AND is for the Wrong Drive. Please, read!

Your LINK http://www.seagate.com/www/en-us/products/external/external-hard-drive/mac-deskt op-hard-drive is for this drive: GoFlex™ Desk for Mac® External Drive which is totaly different than DanDoor's

DanDoor is using FreeAgent® GoFlex™ Desk External Drive, now look for it and see its technical data… I hope you understand this.

As I mentioned before, it MUST be reformated to HFS+ to use backup software for Mac or Time Machine® software

However, I didn't ask you to show me your lack of ethics.

I thought you understood from the beginning that I was talking about this category of ALL Seagate drives:

FreeAgent® GoFlex™ Desk External Drive

You're not getting it, still?

GoFlex™ Desk for Mac® External Drive is formatted by default for MAC (and suggested by you)

FreeAgent® GoFlex™ Desk External Drive by default is formatted for MS Windows (this is what DanDoor has)

Both types of HDDs are compatible with both OS' - the only difference is that they are pre-formatted for a particular system, so the user doesn't have to spend time reformatting for his/her machine.

You nitpicking trough phrases to get me with something I missed or, I wrote?

Here's my lo-tech solution (if you have Parallels) to this frustrating problem:

Eject your hard drive.

Unplug (USB) your hard drive from the MAC .

Start Parallels.

When Windows has started, plug your drive back into the MAC.

You should get a little screen asking if you want the drive to be utilized by MAC or Windows. Select Windows.

Use Windows to copy your files over to the hard drive.

This is less than ideal and not a long-term solution, but I was afraid of attempting any reformatting since I have many files on my hard drive.

Just remember that Windows has to be running first, before you plug in your hard drive.

Endlessindigo, has that solution (simply starting Parallels, starting Windows, then plugging in the external hard drive and clicking on "Use Windows to copy your files over to the hard drive") worked for you?

Doing this, can you freely read from AND write to the external NTFS hard drive from your Mac without need for any third party NTFS app like Tuxera or Paragon?

Yes, I can freely read and write to the external hard drive from my Mac by starting Parallels, waiting for Windows to start, plugging in the hard drive, and selecting "Windows" when asked which OS I want to utilize the drive. I do not have any third party apps. Perhaps I just got extremely lucky, but this has worked on 2 external hard drives, and I hope it might be a solution for other users.