Time Machine-My Passport problem

NicoleK01 wrote:

I am having difficulty backing up my computer to my new My Passport (WD 2tb) external drive. I can see the device has been installed on my desktop, but when I go to add it as a device in Time Machine, it says it can't unmount it. Any suggestions on how to get it to work? Or does this version of My Passport not work with Time Machine? Thanks!

How is the external drive formatted? It should be GUID APFS. If not, open Disk Utility and select View => Show all devices and then erase/format the external drive at the hardware device level (highest level) and choose GUID APFS for the format. This will clear out all contents from the drive, so copy anything from the drive first that you want to keep.

Open System Settings => General => Time Machine and hit the "+" button to then add the drive as a backup destination drive.

WD My Passport drives work fine for Time Machine backups, we are using at least half a dozen on various Macs here.

NicoleK01 wrote:

Thank you. I got it to recognize the Passport, but it says it's going to take 1 day to back up. I last backed up on a different external drive around 11/1, so I find it hard to believe it's going to take this long. I see "GUID partition map" when I go into Disk Utility. Is there a way I can change that to what you suggested- GUID APFS?

As I said, I use that model of drive for some of my Time Machine backups (I have been transitioning to SSD drives which are much faster, but they cost maybe 3x-4x more). Typically they back up at ~ 100 MB/s, so for 1 TB to back up that would take ~ 3 hours or so. The time remaining estimate can be inaccurate at the beginning, it improves as the backup proceeds. Even so, after the first LONG backup, subsequent ones typically take a few seconds or maybe a few minutes, as they are just incremental, only changed or new files are backed up. In comparison, the SSD drives work at 500-1000 MB/s and a complete backup for me takes about 20 minutes, incremental backups and then less than a minute after that. If your backup started. It sounds like you have the correct format (Time Machine would have informed you if you did not), but File => Get Info on the drive should show APFS for "format."

The first Time Machine backup (or the first in months) archiving to a slow device can take a day or two, if there’s a whole lot of data, or (for a subsequent backup) a whole lot of churn.

For subsequent and more frequent backups, Time Machine only archives what has changed, and that completes far faster.

There’s no mention of drive speed in the WD Passport HDD tech specs, which usually means it’s a slow HDD. I do see a listing on one of the reseller websites, showing 5400 RPM. Which is quite slow, even for a hard disk. For a whole lot of writing (backups), that 5400 RPM hard disk drive is probably good for 60 I/O operations per second. Maybe 80. For comparison, SSDs routinely do 100,000 I/O operations per second and quite often more.

If you have the budget for it, another option for easier and more frequent backups is network-attached storage (NAS) box, which will allow Time Machine backups to happen whenever the MacBook Pro is connected to the Wi-Fi with the NAS. This makes the backups easier, and avoids needing to cable anything to the Mac.