How-To: Formatting a new Hard Drive or SSD in Apple Disk Utility

re: Installing an 18TB Hard Drive into the OWC Mercury Elite Pro
re: Formatting a new Hard Drive or SSD in Apple Disk Utility
re: TESTED: Western Digital 18TB Ultrastar DC HC550 hard drive in OWC Mercury Elite Pro USB 3.2 enclosure

When buying a new hard drive or SSD, it needs to formatted before it can be used. This step-by-step walk-through shows how easy it is to get started.

CLICK TO VIEW: Recommended Storage

1. Warning dialog for new drives

When the Mac first sees the new drive, it might be in an unformattted, uninitialized state. So expect to see this dialog pop up. Click Initialize… to bring up Disk Utility.

If you do not see this, then the drive is either not seen by the system (diagnose/fix), or it is already formatted. IMPORTANT: if the drive is already formatted, it might be formatted for a Windows PC (e.g. FAT32)—erase it as per Step 2.

macOS alert with new unformatted drive

2. Erase the drive in Disk Utility

[See note] Select the new drive, and click Erase. When prompted, enter a name for the volume (“Work” as shown here), and choose the format and scheme, as shown below.

Use Format: Mac OS Extended (Journaled) for hard drives, and Format: APFS for SSD. Always use GUID Partition Map for macOS.

It is best to first choose View ==> Show All Devices so that both drives and volumes appear in the list at left (if not showing, choose View => Show Sidebar). This is important (in part) to make sure you are working with the new drive, which should not have any volume listed under it (“Mercury Elite…” as shown here).

macOS Disk Utility prompt to erase a drive

3. Observe the successful result

When Disk Utility finishes (up to a minute), confirmation will be given. Here, the new volume Work is now shown listed under the drive (Mercury Elite…).

An error should not occur, but Disk Utility has quite a few bugs. Occassionally it might be necessary to try again.

macOS Disk Utility confirmation after Erase

As a final verification, select the new volume in the Finder, and choose File => Get Info. In this case the drive is 18TB capacity, and that is confirmed as shown.

macOS Finder Get Info dialog showing 18TB volume

4. If the new volume is a backup, treat it as such

If this new volume is to be a backup, two things are advisable:

• You don’t want the system making backups of backups. Exclude all backup drives from Time Machine.
• Usually it is unwise to have backups indexed by Spotlight—this can result in opening the wrong files, working on them thinking they are originals, then having them wiped out at the next backup (yes this has happened to me!). So exclude all backup drives from Spotlight search (those that are not Time Machine backups themselves).

5. You’re done. The new volume is ready for use.