Here's another tutorial that explains how to do that: If you have Windows computers as well and would like to access (read and write to) the external from both operating systems, then you'd need to use the exFAT/FAT32 file system. Here's a tutorial that can help you with that: If you plan to use the external only on Mac OS computers, you can simply change the file system to HFS+ and reformat the drive. However, keep in mind that if you have any data saved onto it, it will be erased. You can easily change that by re-formatting the drive. My guess is it's formatted in NTFS and that's why it turns up as read-only on your Mac.
Can you tell me the model of the external drive though? You can check the product page of the drive on our website and see if it comes pre-formatted for Windows OS or Mac OS X. I'm sorry to hear about your problems with your brand new WD external.
