Why can't I get my 2TB Passport Ultra to work with my Apple Express router?

I re-formatted my new 2TB WD external hard drive to work with Time Machine on my MacBook Pro, but when I connected it to my Airport Express router Time Machine no longer will work with it. It tells me that the backup disk is not available.
It’s formatted the right way, with one partition, GUID and Mac OS Extended (Journaled), and non-encrypted. We backed up 4 computers to the 1TB Seagate through the Airport Express, and formatting that one last year was easy. But I’ve formatted and reformatted this WD drive multiple times, and every time it’ll work if I plug it in to my laptop and start Time Machine, but I’ll get that error message when I plug it into the AE (it’s the flat one, not the tower). I’m beginning to think that this hard drive is incompatible with Time Machine. Any ideas?

deleted comment, please remove.

Isn’t this the right place to post? I’m trying to use my Passport to wirelessly back up several computers through an Airport Express router, and not having any success.

OK, a couple of things. Your message has now been posted in the correct forum by a moderator. Before, you were in the My Passport Wireless forum and that is what I said to you, Your passport is not a wireless type which is different than all the other hard drives that need to be connected to a computer, The wireless one doesn’t need to be connected to a computer. Now, what I wrote to you is wrong and I will edit my comment or delete it if I can.

So, you are starting fresh, I don’t have your equipment, so someone else needs to help you out.

Do I need to re-post somewhere to have my question seen? My Mac guy has been doing some research, and has found that some people have issues with using larger hard drives with the older AE, which is what I have. I’m thinking that I may need to buy a newer AE (the tower, rather than the flat one I have). Your thoughts?

No, you don’t need to repost. this post jumps to the front of the queue each time there is a reply to it.

Routers usually do not affect hard drive performance. large HDs can affect computer and devices they are connected to sometime, but then I suppose your Mac would tell you so. Maybe you just have an older and slower router that may not even be an N-type router.

Why (and how) are you connecting HD to router, anyway? All you need to do is connect the HD to a computer – no router involved. If you have a functional home network, then perhaps that is why. I have a HD connected to my router, but not for back up. It holds media files I can stream from router to devices at home or away.

So don’t go spending money on a new router just yet. You may not need one. And, if it turns out you need one, you do not have to buy an overpriced one with an Apple logo on it. Last year I replaced my daughter’s old Apple 1st gen N router with a newer one. It does more and cost less. It could be that Apple routers have some special bells and whistles for adding features for Mac devices. But, I doubt it, and it appears you would have difficulty even finding out that it does since you differentiate routers by using words like towers and flat ones. That is no differentiation at all!

Like I said, let an Apple fan help you out.

Thanks, Mike. Since I wrote last, I did some research. Although the router isn’t too old, using 802.11ac (but can accept devices using N, B, and other earlier versions), it seems that it may be incompatible with the WD hard drive. I’ve been referring to it as the AE flat version, which is the Airport Express as opposed to the Airport Extreme, which is the tower (if 6 inches is considered towering, that is). I think I’m going to buy a Time Capsule, which is the Airport Extreme with a built-in 2TB hard drive. The Airport Extreme is $200, pretty expensive for a router, but adding the hard drive to it isn’t much more than the WD hard drive cost. We had a whole bunch of Linksys and Netgear routers, which should work well with Macs, but had nothing but trouble until we went with the Apple router. We were using the hard drive to back up all computers on our network, except for the iMac in my studio, which has its own 1TB hard drive. The 1TB Seagate hard drive that backed up our computers (5 Macbook Pros and a Windows 10) plugged in via USB to the Airport Express, and got its power from the router. Although it doesn’t seem to make a lot of sense to me, the 2TB may need its own power supply to work with the Airport Express.
But no worries, anyway. I can afford to buy the Time Capsule, and I’ll use the WD hard drive to back up my studio computer; its hard drive is almost full, anyway. I think this will solve the problem. I think there must be some secret sauce in the Mac products that make them work together better than third-party gear; it’s worth it to me not to spend hours of time making those other units work if I can simply plug in the Time Capsule and be good to go.
So it’s been a learning experience, and I’ll let you know if I have any problems going forward with the Apple gear. I don’t expect to, though, but I’ll share anything I learn if that is the case.

Thanks for more info.

Is all this concern for a home or a work environment?

The Apple router you have, the 802.11ac standard one, is the most current standard of only the past few years (I believe the previous standard was the 802.11n). The 802.11ac is much faster than the previous standard. Here is one of a few articles explaining the difference:

In other words, you have a most excellent router. I believe the issue is with the WD hard drive; I have read about some drives (WD ones included) that have trouble connecting to routers. Before you self-diagnose a problem with your limited router skills, you need to contact WD Support and see how they can help you!

I am concerned you will replace a perfectly good router for another and still have the same issue!

Also, you mention you have quite a few computers, all with HDs attached to them. You also want to access a drive connected to you router the various computers can access. This is kind of “old-fashioned” in many ways today. Why? Because a lot of people have substituted this solution with another one; by having a NAS connected to their router network. I have. If you don’t know what a NAS is, here is the link at WD telling you all about it. Look it over, it may be just what you need, and WD has a lot of choices, from basic to more elaborate NAS devices. I happen to have a NAS in the latter group.

Also, what is the name and model of the new WD 2TB drive? You just may be able to return it to seller and use that $200 toward a NAS.
Let me know what you think of all this.