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reading and writing on external drive with Mac & PC


macrumors member
Original poster
Jan 1, 2012
I just bought a Mac, have always been a PC person. Arrghhh, I should have stuck with PCs!!!! Much less hassle. Stupid me. But so be it, too late.

Okay, so my new mac (MacBook Air with expensive SSD drive, only 128 gig) has a much smaller hard drive than my old PC (ancient and well-used and slowly breaking Acer TravelMate with 256 gig), so I bought a Seagate external hard drive on which to store my very extensive photo collection so I wouldn't need such a big hard drive in my computer, and also to use to back up my new Mac from time to time.

The instructions on my drive said that if I wanted to use it on Mac and PC I should not follow their formatting system, so I didn't. I copied tons of files onto the drive and transferred them onto my new mac. Then copied tons of other files from my PC - my photo collection - and didn't transfer them, since there isn't space. Also loaded a bunch of videos and stuff onto the external drive.

Now I discover that I apparently can't actually write on the external drive with the mac. Which means it is useless as a backup. And I can't download future photos onto the external drive. (I also can't figure out how to download them onto the mac at all, and haven't found a freeware photoshop clone for the mac, but those are separate problems.)

Is there anything I can do about this? Especially anything I can do about it without having to reformat the external drive and then re-back-up everything that I've already stored on it (the photos & videos)?

I always knew macs were a *&%^$ pain! I should have just gone with the much cheaper and slightly lighter Toshiba ultrabook, and figured I'd get used to the crummy keyboard... Grrrrrrr. :mad:

But okay, what's done is done, no use crying over spilt milk, and I realize I am asking these questions of people who think macs are the greatest thing since sliced bread! So I guess I should keep my opinions to myself. And also thank the folks who provide info in these discussions - I've gotten tons of useful info here already, which I greatly appreciate. :D


macrumors newbie
Jan 2, 2012

Sounds like your having just as much fun as me with this recent switch over - you'll need to check what current format your hard drive is in. Go ahead and open Disk Utility and click on the Partition not the drive that you want to check and it will display the information at the bottom left.

You are more than likely in NTFS which is what most external hard drives come as, if you do not want to move everything around and format to a more native support for your Mac you will have to get an extra program to do it for you.

One such program is NTFS for Mac by Paragon

Personally I chose the format option, it's three weeks later and I am still in the middle of formatting drives lol.
Nov 28, 2010
Yeah, Macs are useless *****, but ignorance is more *****.


Overview of the four major file systems (called "Formats" in Mac OS X) used on Windows and Mac OS X, compiled by GGJstudios. You can use Disk Utility to format any HDD to your liking.

Any external hard drive will work with PCs or Macs, as long as the connectors are there (Firewire, USB, etc.) It doesn't matter how the drive is formatted out of the box, since you can re-format any way you like. Formatting can be done with the Mac OS X Disk Utility, found in the /Applications/Utilities folder. Here are your formatting options:

FAT32 (File Allocation Table)
  • Read/Write FAT32 from both native Windows and native Mac OS X.
    [*]Maximum file size: 4GB.
  • Maximum volume size: 2TB
  • You can use this format if you share the drive between Mac OS X and Windows computers and have no files larger than 4GB.
NTFS (Windows NT File System)
  • Read/Write NTFS from native Windows.
  • Read only NTFS from native Mac OS X
    [*]To Read/Write/Format NTFS from Mac OS X, here are some alternatives:
    • For Mac OS X 10.4 or later (32 or 64-bit), install Paragon (approx $20) (Best Choice for Lion)
    • For 32-bit Mac OS X, install NTFS-3G for Mac OS X (free) (does not work in 64-bit mode)
    • For 64-bit Snow Leopard, read this: MacFUSE for 64-bit Snow Leopard
    • Some have reported problems using Tuxera (approx $36).
    • Native NTFS support can be enabled in Snow Leopard and Lion, but is not advisable, due to instability.
  • AirPort Extreme (802.11n) and Time Capsule do not support NTFS
  • Maximum file size: 16 TB
  • Maximum volume size: 256TB
  • You can use this format if you routinely share a drive with multiple Windows systems.
HFS+ (Hierarchical File System, a.k.a. Mac OS Extended (Journaled) Don't use case-sensitive)
  • Read/Write HFS+ from native Mac OS X
  • Required for Time Machine or Carbon Copy Cloner or SuperDuper! backups of Mac internal hard drive.
    [*]To Read/Write HFS+ from Windows, Install MacDrive
    [*]To Read HFS+ (but not Write) from Windows, Install HFSExplorer
  • Maximum file size: 8EiB
  • Maximum volume size: 8EiB
  • You can use this format if you only use the drive with Mac OS X, or use it for backups of your Mac OS X internal drive, or if you only share it with one Windows PC (with MacDrive installed on the PC)
exFAT (FAT64)
  • Supported in Mac OS X only in 10.6.5 or later.
  • Not all Windows versions support exFAT. See disadvantages.
  • exFAT (Extended File Allocation Table)
  • AirPort Extreme (802.11n) and Time Capsule do not support exFAT
  • Maximum file size: 16 EiB
  • Maximum volume size: 64 ZiB
  • You can use this format if it is supported by all computers with which you intend to share the drive. See "disadvantages" for details.


macrumors 65816
Jul 28, 2004
Portland, Oregon
From Wikipedia -
Mac OS X
Mac OS X 10.3 and later include read-only support for NTFS-formatted partitions. The GPL-licensed NTFS-3G also works on Mac OS X through FUSE and allows reading and writing to NTFS partitions. A performance enhanced commercial version, called Tuxera NTFS for Mac, is also available from the NTFS-3G developers. Paragon Software Group sells a read-write driver named NTFS for Mac OS X, which is also included on some models of Seagate hard drives.

Even a small amount of research before you made your purchases would have left you better informed. If you buy stuff you don't know much about, against your own better judgement, run into problems and then register on this forum to whine about problems that have well identified solutions, then you should expect to get some flak.


macrumors member
Original poster
Jan 1, 2012
Good gracious, I don't think I should have to be a computer geek in order to buy a new laptop and start using it! I don't want to have to know details of file types or which kinds of formatting are possible on which systems. In 24 years of working on laptops (yes, I started on them when they had dual floppy drives) and luggables before them, 30 years as a user of PCs, several years managing software on the hard disks in a lab full of PCs used by several 100 students in the pre-windows days, and even writing a dissertation on the impacts of end-user-computing technology on data use, I have never needed to know this kind of thing. If shifting from PC to Mac calls for this kind of knowledge, then it definitely doesn't make sense! Especially as all my Mac friends assure me that they are actually much simpler than PCs.

All of that being said, this turned out to be an issue with the external drive, not the computer (and there are a LOT of discussions of this problem on the Seagate user forum). Or more accurately, the lack of documentation on how to install the external drive. With a little scouting I figured out what was needed, and now my new Mac can write on on the drive. Without any need to know anything technical about file formats - whew!

And my apologies for posting the query before figuring this out. Usually I know better than to hit "send" - or "submit," in this case - when I'm still mad!
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