mac does not see external hard drive

The Mac's OS can read the NTFS format, but it cannot write to it. However, it should currently appear in Disk Utility when connected.

but now mac wont recognise the drive

Does "now" mean it was previously recognized in Disk Utility?

If you want to make the drive read/write for BOTH the MacBook and Vaio (and you still have access to the Vaio), use the Vaio (Windows) to reformat the drive as FAT32 (instead of NTFS). Macs can read/write that format. (This will erase the drive's data, so you'll need to copy the data off the Vaio again.) After reformatting it with the Vaio, connect it to the MacBook to confirm it is recognized.

NOTE: If you want to use the drive with a Mac (after transferring the Vaio's data), and you don't need to connect it to the Vaio anymore, you should reformat it using Disk Utility, with format set to Mac OS Extended (Journaled). That is the Mac's "native" disk format.

this is a new mac, i never tried this HD before with the MAC. Now i've formatted the HD in to exFAT using my vaio, coz that is the only available format other than NTFS. still no luck. my MAC doesn't recognise the HD, i can see the light on HD when connected to MAC. but i cant find it on disk utility either....

Since this is a new Mac, have you tried connecting something else (that is a storage device) to that same USB port? For example, if you have a USB flash drive (or another external drive), that would be a good test, to confirm the port is working properly.

An external drive should appear in a Finder window, in the sidebar, under DEVICES. And it should appear in the Disk Utility sidebar.

yeah i tried connecting my 4GB sandisk USB flash drive, was working fine. i cant see my HD neither on disk utility nor on finder window. The nearest apple store is 150 miles from where i live. please help. thank you

It seems you have ruled out a problem with the USB port, since you can use that 4GB flash drive there. And the USB cable is fine, since it works with the Vaio.

So that may point to some incompatibility with the Seagate external drive, either in its hardware or based on how it is set up. Do an About this Mac from the Apple Menu, and then click More Info (then System Report). In the System Information window, under Hardware -> USB, do you see the Seagate external drive listed (when connected).

Be sure to connect the MacBook's power supply, so that it is not running on battery power. You can also try starting it up in Safe Mode, in case there is some third-party extension that is interfering.

OS X: What is Safe Boot, Safe Mode?

thanks for being patiently running me through the process of solving my issue. i cant see my HD under USB in system information window even when the system is in safe mode. now i will try to reset the computer to factory settings, may be that will help...

hi, now i have reset my macbook to factory settings, still i cant see my hard drive in disk utility or finder window when connected. i can use the flash drive using same usb port. please help... now am planning to buy a new hard drive, but was worried what if the same repeats...?

FWIW, I bought a new WD Passport external 2TB drive and it was not recognized by Disk Utility (and also not mounted) on my Mac Pro - nor were my other external drives - even though all of them mounted on Windows OS with the same cables. In order to resolve the issue (thanks to posts like this and others) I had to disconnect all USB cables (printer, SD card reader, etc) except for keyboard, reset PRAM/NVRAM a couple of times (About NVRAM and PRAM). Once that was completed, all my drives started mounting again.

Thanks for all the assistance on this thread!!

i have the same problem but device doesnt turn up in disk utility either

Did this external hard drive previously work with this particular Mac, and does not now for some reason, or is this the first time you are trying to connect it?

Have you ruled out possible problems, as described in this topic thread, such as a bad USB cable, problem with USB port, conflict between connected devices?

What type of external hard drive is it? USB 2.0, USB 3.0, FireWire, Thunderbolt, etc.?

What's your Mac model, and OS X version?

Hi Kenichi,

I'm replying to an old post in the hopes that you can help with a similar problem. My Samsung HD appeared as "read only" after a Mac OS update, so I reinstalled the driver, which had worked before when I encountered the same. However, now my Mac doesn't recognise the HD at all, and in Disk Utility I see the following:

It would appear the Mac isn't connecting at all to the HD - it also displays it as full storage, which isn't true.

Do you know any resolutions to this, that don't entail erasing the HD?

Many thanks!

Yes, this is an old topic... 😎

In the first screenshot, Partition Map = Master Boot Record. That may indicate this external drive was purchased with Windows formatting (such as NTFS) and never reformatted to a native Mac format, which would be more appropriate for use with a Mac (unless this external drive needed to go back and forth between a Mac and Windows PC). The default settings for Disk Utility to Erase (reformat) a drive would make Partition Map = GUID Partition Map AND Format = OS X Extended (Journaled).

My Samsung HD appeared as "read only" after a Mac OS update.

NTFS is read-only with the Mac's OS X, and so that fits. There are third-party products that can allow OS X to read and write NTFS; an Internet search on "mac ntfs" shows a few. You mentioned reinstalling a "driver" (not something most Mac users do to fix an external drive issue), so you may be using one of those third-party "NTFS for Mac" products. For that product (if you are using one), did you check the developer's web site for a compatibility update (to that driver) related to the OS X update? It would be up to the developer to maintain compatibility with OS X, since it's not something Apple would test.

If an incompatible driver is currently installed, that may the reason for the second screenshot issue, with no access to the drive's volume. Normally, if the drive is formatted using NTFS, OS X should at least be able to read it.

Than you Kenichi!

The driver I'm referring to was simply the installation driver for mac that appeared in a folder when opening the HD before. It installed the driver and then prompted a restart, after which the HD doesn't show up at all in Finder, and in Disk Utility as shown above. I don't know if the installation somehow corrupted the HD (which it obviously shouldn't).

It has worked perfectly on my Mac before, except for the "read only" mishap, which I managed to resolve once before. I have lots of files etc on the HD and am afraid it's all lost.

So, now my question is - is there any way to bring back the HD from the beyond, or is it doomed by a faulty installation? If I can just get it back (even as read only) that would be a miracle right now.

The driver I'm referring to was simply the installation driver for mac that appeared in a folder when opening the HD before. It installed the driver and then prompted a restart

That's not a normal thing... External hard drive that are formatted for Mac do not need a special driver to make it work. I suspect this Samsung drive is targeted at Windows customers, so it is formatted for windows (probably using the NTFS disk format). Rather than advise Mac customers to reformat (Erase) the drive using Disk Utility, maybe they included a driver that allows OS X to read and write to the drive as is.

So, before installing that special driver, I think you said the drive was read-only. That would make sense, if the drive is formatted using NTFS. If you run the installer for that driver again, does it have an uninstall option. If it does, uninstall the driver and restart. Hopefully, the drive will be read-only again. Then, you can at least copy off your files to another drive (that is preferably formatted for Mac).

Also, I did an Internet search on "samsung external drive mac driver," and this link came up

http://www.seagate.com/support/downloads/item/samsung-ntfs-driver-master-dl/

The description says

This software will allow the Samsung external drive to be writable without the need to reformat from the default NTFS partition. Without this driver the NTFS partition is read only. If you have reformatted the drive to HFS+ format then this driver is not needed.

"HFS+ format" is the Mac format. If this version is newer than the one you installed (and it's the same Samsung product), it may fix your problem.

I can't get to the folder and run the installer because the HD doesn't even show up in Finder. It's as if my mac doesn't recognise it at all now. So any attempt at uninstalling is out of the question, until I find a way for my Mac to detect the wretched thing....

What you write about the format makes sense and corresponds to my experience. But unless I can figure out a way for my Mac to detect the HD, the format becomes a moot point...

Thanks so much for your help. I don't want to take up more of your time given that the HD has vanished as far as my Mac is concerned! Not sure where to get help with that - but thanks again, appreciate it!