How do I initialize a brand new hard drive in Mac OSX?
Before you can access a new or formatted drive in your operating system, you need to initialize it first and then create a partition on the drive. A partition defines an area of the drive to use for storing data. The partition uses a file system (for example, HFS+, ex-FAT, NTFS, and so on).
Initialize a drive
Mac OSX detects a drive that needs to be initialized and automatically prompts you to initialize the drive. If you are prompted to initialize the drive, click Initialize. If you are not prompted to initialize the drive and you cannot find the drive in Finder, you will need to create a partition on the drive.
Create a partition on a drive
Note: The following steps create an HFS+ (Mac OS Extended (Journaled)) partition that uses the entire drive space.
To create a partition on a new drive, complete the following:
Navigate to Applications and click Utilities.
Open Disk Utility.
Select the new drive and click the Partition tab.
Click Options and verify that it is set to GUID Partition Table.
Enter a name for the partition.
The drive should now be accessible in Finder.