Can NOT mount new Passport external drive.

You're almost there. Note in the screenshot you provided, your My Passport is already selected. Also note the line under My Passport stating Microsoft NTFS. That is telling us that this drive is currently formatted in NTFS.

What you need to do to change it to APFS, is select the "Erase" option. Be sure that only the My Passport is selected.

Then follow the steps in this Apple Support article erase & format this drive for APFS:

• Erase and reformat a storage device in Disk Utility on Mac - Apple Support

SLibrarian wrote:

...Yes, it does show up on the top row of icons, etc and also under the icon NTFS For Mac menu. At the bottom, the icons for NTSF For Mac and WD Discovery also show up.

Ah, there's the issue. Macs can read from NTFS-formatted drives, but can't write to them natively. In addition, TM cannot use them, in this format, for backups.

What I suggest you do is use the Disk Utility to completely erase the drive, and then, format it for APFS.

Sorry, HFS+ if a drive's file format. HFS+ & the newer APFS are Apple formats, with NTFS is Microsoft's version.

How you can tell which format an external drive is currently using would be via the Mac's Disk Utility.

To do so:

1. Run the Disk Utility, located in the /Applications/Utilities folder.
2. Then under the "External" heading in the left-side window, select your WD drive. I included an image of my system for reference. Note that this image, I took earlier, is highlighting my Mac's internal drive.
3. Look for either HFS+ or APFS. If it still shows NTFS, the drive will need to be reformatted.

Thanks for confirming what your drive is.

Ok, that confirms my suspicions ...

... taken directly from the WD website:

Works on Windows and Mac

My Passport Ultra is formatted for Windows® 10+ to deliver plug-and-play storage out of the box. With WD software, you can also download the NTFS driver for macOS, so you can work seamlessly between operating systems without reformatting.

Unless you have a need to use this same drive with Windows computers, I do not recommend that you install the NTFS driver for macOS as stated in that paragraph. TM will only work with drives formatted in either HFS+ or APFS. Since your Mac is running macOS Ventura, I suggest going with APFS.

Ref: Backup disks you can use with Time Machine - Apple Support

Just to be sure I understand your post ...

... Can you successfully mount this external drive to the Mac? That is, does it show up on the macOS Desktop after you plug it into your MacBook Air?

If so, are you saying that when attempting to use it for Time Machine (TM), that TM does not recognize it or allow its use for backups?

What format is this drive using? HFS+, APFS, or something else. You can verify this with the Disk Utility.

Finally, did you use this drive with TM from the old Mac? ... or is it completely "new?"

Hi @Katana-San

Although we should wait for the OP to verify the actual drive model, I have been using these drives for years now. They typically come in two "flavors:"

1. Those that are formatted in HFS+ for Macs, and
2. Those that are formatted in NTFS for Windows PCs.

Both, of course, can be reformatted as required.

SLibrarian wrote:

...Do I need to delete any software or anything? The green dot on the Mac hard drive in Disk Utility, not to worry about that? I expect when I click 'erase', it'll have 'are you sure' types of questions. Why did this whole fiasco even happen? Anything else you think I need to know, which is a lot...no doubt?

No, and no, for the first two questions. Most likely this fiasco happened simply because you tried to use a drive, meant to be used with Windows computers, with a Mac. Fortunately, as you now know, that issue was resolved by just reformatting it so your Mac, specifically Time Machine, can use it.

... and no there is nothing else I can think of at this point.

You're very welcome!

Fantastic! Great job! I'm sorry this was more of an ordeal than it should have been. Most of us here are volunteers, as most, if not all of us, have gone through similar issues. I'm one of those. I was so impressed by the help I received from others, that I decided to try helping others as well. Sort of a "pay it back forward" kind of thing. Started doing so in 2006. Became addictive. You never know, you may become our next Disk Utility guru and find yourself doing the same.

Hello ~ Just out of my own curiosity….what model Passport external?

~Katana-San~

Hello ~ So good to see you! I was just curious for there is a post in the WC about some issues but probably totally unrelated here. Good work as always 🙂🙂

~Katana-San~