Problem with Time Machine, ASUS router and Seagate hard drive

It is my understanding that the ASUS router will not mount, network or recognize a hard disk in APFS format

This is correct, but neither will an AirPort Extreme, if you still had one.

As I said, set things up with the Asus router and Seagate hard drive the same way that you would set up the AirPort Extreme and a Seagate router.......with the hard drive formatted in Mac OS Extended (Journaled), also known as HFS+

No matter what operating system you might be using on your Mac, if you are backing up multiple Macs to a network destination, the hard must be formatted in the correct Mac HFS+ format. Time Machine will not back up over a network to a drive that is formatted in APFS.

APFS format will work for the hard drive if it is connected directly to a Mac so a single Mac can back up that way. But other Macs will not be able to back up to the same drive over the network.

Bottom line......if you want to back up multiple Macs using Time Machine, the hard drive must be connected to your router.....and.....the hard drive must be formatted in Mac OS Extended (Journaled), aka HFS+.

Check with Asus support for up to date details on setting up a hard drive for Time Machine backups.

Set the AirPort Express aside, unless you want to use it for AirPlay. The Express will not support a hard drive at its USB port, no matter how the hard drive might be formatted.

First issue here is that an AirPort Express does not support a hard drive at its USB port. The only thing that will work at the USB port is a USB printer.

So, no sense in trying to do anything else with the AirPort Express unless you want to use it for AirPlay.

So while all my Apple computers are able to connect to the new network through the Asus routers, some of my Apple computers cannot see the Seagate backup drive, even though the backup drive is plugged into my laptop.

The backup drive needs to be connected to your router to make it a network drive. I haven't checked with your specific Asus router model, but most of the Asus routers will support Time Machine backups to a drive connected to the USB port on the router.

Another way to say the same thing, you would want to connect your Seagate drive to the Asus router the same way that you connected a hard drive to the USB port on an AirPort Extreme.

Check with Asus Support for more details. Example:

https://www.asus.com/us/support/FAQ/1004458/

EdwardAHavens wrote:

It is my understanding that the ASUS router will not mount, network or recognize a hard disk in APFS format, the required format for Time Machine since macOS Big Sur...

Even with the very latest version of macOS (now, Ventura), TM will still back up to (directly attached) external drives formatted in either APFS or HFS+. However, to be the most efficient, versions of macOS that use APFS-formatted system drives, work best with external drives formatted the same. Regardless, neither the AirPort Extreme, nor the Time Capsule (internal or external,) ever supported APFS drives.

For network drives, like those in a NAS, they do not need to be formatted for either of these. For example, the Synology NAS, which does support TM backups, uses internal drives formatted in btrfs.

If you connect the Mac OS Extended drive hard drive directly to a Mac's USB port, Time Machine will automatically (without telling you) reformat the drive prior to the first backup in APFS (Case Sensitive). That is probably why you were surprised to see this format when you checked the drive's format during troubleshooting.

But......if you connect the Mac OS Extended hard drive to a network location.......the USB port on an AirPort Extreme or the Asus router.....the drive will remain formatted as Mac OS Extended (Journaled) and the Time Machine backup will go to the Mac formatted disk.

Things get even more complicated.....I will explain later.....but for now you want to make sure that the drive is formatted Mac and connected to the USB port on the Asus router.

If the Asus router does what Asus says it will do, when you go to set up Time Machine from the Mac, the drive will appear as a destination choice, just like it did previously when you were using an AirPort Extreme the same way as the Asus.

I haven't tested this on an Asus router, but I have done this on a Synology router and it works great. Another user reports that this has worked as well on a TP-Link router.

Note.......The Seagate drive must be formatted Mac OS Extended (Journaled)......and.....you cannot assign a disk password , encrypt the disk, etc.

Be sure to use Disk Utility on your Mac to format the drive. Do not use software provided by Seagate to format the drive.

Unfortunately, I do not have an Asus router here to test, so I am going on Asus' claim that Time Machine backups are supported with their router.

I can connect to the Seagate HDD in Finder on my Mac, but I can only see the folder where the backups are stored

If you formatted the Seagate drive in Mac and checked to "see" the drive using the Finder, the Seagate drive should be blank at that point. You won't see anything that has to do with Time Machine because a backup has not yet run.

Please format the drive again and check to make sure that the drive is blank when you connect to the drive using the Finder.

Disk Utility can't see the Seagate drive when it's hooked up to the Asus router.

Correct. When the Seagate drive is connected to the Asus router, it becomes a "network drive". Disk Utility cannot be used with a "network drive". It will only work if the drive is connected directly to your Mac.

That is why you have to have the Seagate drive connected to your Mac to format it using Disk Utility.

When the Seagate drive has been formatted in Mac OS Extended (Journaled) and it is connected to the Asus router, you should be able to get Time Machine backups going.

Here I am assuming that the Asus router will do what Asus claims it will do.

I cannot test the same setup because I do not have an Asus router here to test. I can confirm though that backups work perfectly when a drive is connected to the USB port on a Synology router. There are no special tricks involved with this. The hard drive is formatted as Mac OS Extended (Journaled) and Time Machine starts to back up correctly as soon as it is set up.

I doubt that another user who has set up Time Machine backups to a drive at the USB port of an Asus router will see this post on a support site for Apple routers and be able to help us out, but we can hope.

Other than checking to make sure that you have the latest updates for the Asus router, I cannot think of any other suggestions that I can offer at this point.

I don't think MacRumors is talking about a network drive that is connected to a USB port on a router.

The point that I'm trying to make is that if the drive is formatted in Mac OS Extended (Journaled), Time Machine will automatically re-format the drive in APFS if that is what Time Machine wants to use. This would be the case for newer operating systems like Big Sur, Monterey and Ventura with drives that are connected directly to the Mac.

That is why you were surprised to find out that your Seagate drive was really formatted in APFS when you originally formatted in Mac OS Extended (Journaled). You connected the drive directly to your Mac and Time Machine reformatted it without you knowing about it

Example.......I formatted a new hard drive in Mac OS Extended Journaled a few years ago to connect directly to my wife's iMac running Big Sur. Time Machine automatically reformatted the drive in APFS when I ran the first backup.

But......There is no way that Asus can offer support at the USB port of their routers for a drive that is formatted APFS. The only way that a hard drive can work at the USB port of an Asus......whether it is using Time Machine or not......is if the drive is formatted in Mac OS Extended (Journaled).

The short story........format the hard drive in Mac OS Extended (Journaled), no matter whether it will be connected directly to a Mac or to the USB port on a supported router.

Time Machine will automatically take care of the rest and format the drive connected directly to the Mac in APFS. If the drive is formatted Mac OS Extended (Journaled) and connected to the USB port on a router, Time Machine will leave that format alone......because the USB port cannot support drives formatted in APFS.

If you want to connect the drive to the USB port on the Asus router....or any other router for that matter that claims to support Time Machine......the drive must be formatted in Mac OS Extended (Journaled).

If you do format the drive in APFS and connect to the USB port on the Asus router, I can guarantee that the Asus router will never "see" the drive.

What we need is a user to post and tell us that they have set up Time Machine backups to drive at the USB port on the Asus router and things are working fine. That will confirm that the Asus router really does offer up to date support for Time Machine.

All that I can do is confirm that the Synology router fully supports Time Machine. I cannot say whether Asus is making a claim that they cannot deliver on. At some point, Asus Support is going to need to step up and offer some real help to make good on their claims.

I don't think you are going to find much help for an Asus router on a support site for Apple routers.