Replacement of Time Machine backup disk

I've never had to format my WD EHDs, so if you tell me how to do that (which Disk Utility tab: first aid, partition, erase?), I probably wlll follow your advice and format it as APFS-Journaled.

I have bookmarked your link to the OWC Mercury Elite Pro drive, but just FYI, I've been very lucky with my HP My Passports, which have been in service since 2017 and 2018.

So it turns out the Western Digital's got a UCB-C cable, which I can't use on the old iMac, so I'm going to have to get an $8 adapter before I can do anything with it. I think it's the UCB-C to USB one, which costs $19 if by Apple and $8 if by Insignia; both are available at Best Buy. I think I'd have to get an adapter for the OWC drive too, but there's no one available in sales or customer service there on Christmas Eve. I'll wait till Monday to hopefully get answers from OWC.

Another issue I just discovered is that the box says it's for Mac OS 11+. I think Western Digital had told me it would work on 10.11.6, and the one I got before the brand-new one does work fine.

I can't find out where to ascertain if it's OS X EXtended or APFS, but since I never had to format the previous WD My Passport drives, I think it would be unnecessary for this one. I'll check with WD.

So right now everything's on hold, and I'll just continue copying data from my internal HD to the external ones until I can get Time Machine working again.

The Apple USB-C to USB adapter is way more expensive than the others, but it's by Apple, and since it's critical that my data be safe on the new Time Machine hard drive, I just ordered it from Amazon (it's a dollar less there), and if it doesn't work I can easily return it. I won't have it until 12/28, but that's no biggie, since I'm backing things up manually meanwhile. Thanks again.

Jack, thanks.

My iMac is a 2012 model, so your comment about 2011 or older Macs doesn't apply.

I'm going to verify with Western Digital that the drive I bought WILL work on my 10.11.6 iMac, just as the last identical WD drives I have do.

The only issue is the adapter. The one that it comes with won't connect to my iMac. The Apple adapter, as you say, works with connecting my old mouse to my new MacBook Air, but it won't plug into my old iMac, so I'll keep that as a spare for the Air. The other WD drives came with cables that plug right into the iMac. So I'll have to ascertain from either WD or Apple which adapter I should get.

I believe the new WD drive IS formatted for my iMac. At least I've never had to format or reformat the ones I have. I'll check with WD and Apple.

The drive you recommend is kind of overkill for my purpose. It also is slightly too long and wide for where it would have to be placed. My EHDs sit on a small area the desk behind the computer and don't need to have bumpers, since they just sit there and don't risk getting bumped. But I've bookmarked the site and will definitely keep it in mind. Thank you.

Thanks, That looks right, but I'm concerned that it might be for a PC: "This adapter is designed to extend your old USB Type-A laptops, PC, charger, it allows you to connect to USB Type-C cable or other USB Type-C devices.It supports data transfer and charging." And "https://www.amazon.com/dp/B074V4QBS4/ref=sspa_dk_detail_0?pd_rd_i=B074V4QBS4&pd_rd_w=Strn4&content-id=amzn1.sym.386c274b-4bfe-4421-9052-a1a56db557ab&pf_rd_p=386c274b-4bfe-4421-9052-a1a56db557ab&pf_rd_r=YHFN99JBD8ZKZVQP61EN&pd_rd_wg=wf9BX&pd_rd_r=bbff9b85-6597-4e0b-ba7e-190a728ecf9e&s=electronics&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWxfdGhlbWF0aWM&th=1

I need the adapter to be compatible with my 2012 10.11.6 iMac.

What do you think of this one, please?

https://www.bestbuy.com/site/best-buy-essentials-female-usb-c-to-male-usb-adapter-2-pack-black/6541128.p?skuId=6541128

I really am a dufus when it comes to all of this, as you all have probably figured out.

Update: The backup to the new My Passport disk failed. I have a tech support request in to HP.

The OWC disk info says it's okay for my OS 10.11.6, but using Bluetooth (?). I may be ultimately relegated to just continuing to manually back up my data daily onto an external hard drive. But I sure would hate to lose Time Machine.

PS: The current and new EHD are 2 TB.