Using a WD 1TB External Hard Drive from PC to Mac

[cedwhatev]

Hey guys, I am just awaiting the arrival of my MacBook Air, and had a question. I have a Western Digital External Hard Drive 1TB. To be specific, it's this one:

http://www.wdc.com/en/products/products.aspx?id=430

Now, it's for both PC and Mac, but I've only used it on my netbook, which I just sold. Now, I will be using it on my Mac, but my question is, do I have to reformat it, and if so, do I have to remove everything off of it before doing so? I don't know much about this stuff, so I am at a loss as to what to do. I have alot of stuff on it, over 400GB worth, so I don't really want to have to go through all of that, if I don't have to. Any advice?

[simsaladimbamba]

Most probably it will be using NTFS as format, for consequences see below. Thus if you only want to use it in Mac OS X and as Time Machine HDD, it needs to be formatted with HFS+.
Btw, if that data on the HDD and the future MBA is important to you, it is always good to have two backups. I backup my digital(ised) photos and video footage twice, thus I have three copies of it on three HDDs.

Originally Posted by GGJstudios

FAT32 (File Allocation Table)

• Read/Write FAT32 from both native Windows and native Mac OS X.
• Maximum file size: 4GB.
• Maximum volume size: 2TB

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: Install NTFS-3G for Mac OS X (free)
  
• Some have reported problems using Tuxera (approx 33USD).
• Native NTFS support can be enabled in Snow Leopard, 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

HFS+ (Hierarchical File System, a.k.a. Mac OS Extended)

• Read/Write HFS+ from native Mac OS X
• Required for Time Machine or Carbon Copy Cloner 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

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

Helpful Information for Any Mac User by GGJstudios

Time Machine FAQ

[cedwhatev]

OK, so basically, I can only read whatever is on my WD HDD when using my Mac, but can only write onto the HDD using a Windows PC, unless I decide to format it for Mac. Correct?

[simsaladimbamba]

Originally Posted by cedwhatev

OK, so basically, I can only read whatever is on my WD HDD when using my Mac, but can only write onto the HDD using a Windows PC, unless I decide to format it for Mac. Correct?

Basically yes, but you can use software to write to NTFS formatted HDDs. But if that HDD will be solely used in Mac OS X, HFS+ is the better choice.