Time capsule won’t backup via WiFi or Ethernet

Thanks.. that is helpful.

I do also need to see the setup on the computer.

But let me suggest some things to try.

NOTE .. when you have one computer working fine and the other failing.. the most likely cause of the issue is the computer.. not the TC directly.

NOTE .. some changes will do nothing.. but we need to track down the cause which is difficult.

Your setup is very typical.. and no big issues.. so what has gone wrong here is bound up with overlapping OS upgrades.. in the end they do funny things to a computer.

Here is the simple stuff.. Test this and report back.. I have more complex arrangement.. but lets see if simple works.

Numbers points are not working properly.. so I am going to do it with letters.

A. On the Internet tab of the TC change to static.

It is currently set to DHCP.. ie it automatically gets an IP from the ATT router..

When you select static it will basically move the IP it currently has and all the other details to static.. and they won't change thereafter.

Take note of whatever the value is at the time.. Here is the first big problem.. it keeps changing IP. Routers should be static.

B. You have a domain issue.

Look carefully at the domain on the Internet tab of the TC.. and also on your first shot of the broader network.

The domain is attlocal.net

Now look at the second screenshot.. your wirelessly connected laptop has a domain of .local

This is wrong.. and is a bug in the airport. I do not even understand how it is possible with the Airport in bridge and the ATT router handing out addresses..

Go to your computer.. I am pretty sure you will find on the wireless network preferences DNS tab you will have a search domain of attlocal.net

But your computer is in wrong domain.. Please remove attlocal.net and make sure that page is blank.

On the DNS side it should show 192.168.1.254

If it shows ATT dns servers.. replace them with 192.168.1.254

(However this is not a good idea if you are using your laptop outside home and connecting to a different network.. so consider this a test).

C. Fix IPv6 link-local.

In the earlier post I showed you how to do that on your laptop.. did you do it??

You can also now do it on your TC.. go to the Internet tab, Internet Options. Change it from Auto to Link-local only.

Test and see if you get any improvement.. this might take a couple of days.

Even if you don't immediately get an error does not mean it won't happen.

If it fails.. open a terminal and ping the TC.. just type

ping -c 20 192.168.1.87

That is just to limit the pings to 20.. that ensures the TC is awake and running.

I would then mount the TC hard disk in Finder.. you don't need to do anything except open it.

Then see if Time Machine will work.

You can backup directly to the IP address.. but this does not carry over after a reboot.. which makes it a pain.. but if you would like to, again more of a test ..

With the TC static IP.. in Finder use Go, Connect to server.

Type in AFP://192.168.1.87 (or whatever your TC static IP happens to be).

When requested put in your password for disk access.. usually just the main password. store in the keychain.

Then go to Time Machine.. click on add or remove backup disks.

Add the new disk which should show up as a different disk to the TC current name.

Do not remove the existing disk.. and put in your password.

Time Machine will now (120sec delay) check the disk.. find the existing backup and continue with the next incremental.

Tell me how that goes.

Depending on results we can go more complicated .. if it still fails.

Thing I have noticed is that when I go back to check on the backup progress and see it has failed, there is consistently a message about the laptop itself being almost out of space. There’s about 16GB left. Could this be the cause of the problem?

I don' t know the answer......but when I filled up an older Mac laptop here as a test.....I immediately began to have back up problems with Time Machine.

When I brought the Mac back down to the point where I had 50 GB or so of free space, the backups ran perfectly.

I don' t know the answer......but when I filled up an older Mac laptop here as a test.....I immediately began to have back up problems with Time Machine.

Thanks for running that test Bob..

Was this to local or network target??

I presume this is with Mojave??

smsdiego6.. I recommend you follow Bob's test.. before you do any of the other stuff.. and make sure you have at least 50GB spare on the local drive.

I will try and reproduce this test as well.

On my normal desktop Mac running.. El Capo I reduced the free space to about 4GB and ran the backup to local disk and it ran without issues..

I am now doing the test to a TC on the network which is so far doing fine.. another 30min to complete..

When you think about it.. reserving 50GB on a 128GB drive that comes in some of the low end MacBook Air.. by the time you have OS and Applications loaded there would be nothing left.

Did you turn off local snapshots.. I wonder if that is part of the problem?? Local snapshots are important part of Time Machine on the APFS formatted drives.. which is what will happen without your knowledge on both High Sierra and Mojave.

Was this to local or network target??

Time Capsule via wireless.

presume this is with Mojave??

Older laptop.......best it can do is El Capitan

As we know, Mojave reformats any Mac hard drive to AFPS. Not sure how or if that comes into play here.

Thanks Bob..

My backup to the TC completed fine.. I actually swapped between wireless and ethernet throughout the test.. I had no issues..

Backups completed in expected time.

And my head is hurting.. there are just too many factors coming into play here..

Is it possible that this could be from some corrupt file on my laptop that is causing the bottleneck?

If you have not already done so......(I got lost on this thread some time back).......

Open Disk Utility on your Mac that is having difficulty backing up (Finder > Applications > Utilities > Disk Utility)

Select the Mac's hard drive......probably named Macintosh HD

Run First Aid

Try another back up

Just to add to Bob's comment.. if you have a USB drive.. same or larger than your Mac drive..

Then it could be well worth using that as a target for time machine.. That also will prove if the Mac boot drive is having issues.. and if it backs up perfectly may indicate there are other issues.

Plus it is known to be a lot more reliable now to use local drive instead of network.

Am I to understand that CCC could act as a full replacement for TC?

Not exactly. Time Machine keeps a complete history of how your Mac looked at any given time in the past.

CCC makes a complete copy or "clone" of your Mac on the first back up and then it backs up any changes to your Mac on future backups, so you basically have one backup of your Mac that is up to date with the last backup.

There is a very limited option to keep some history of backup changes with CCC, but you should not think of it as an exact replacement for Time Machine if you are used to going back in time to pick up a file or folder that might have been deleted in the past.

A really good back up strategy might be to use both Time Machine backing up to a USB drive connected directly to your Mac and CCC doing the same, or backing up to a Time Capsule. 99% of the issues with Time Machine have to do with backing up to a Time Capsule which has frankly become an unreliable backup method since High Sierra and Mojave have been introduced.

CCC is a cloner.. It creates an exact image of your computer.. every time it backs up the latest files are included in the clone so it exactly matches the computer at the time.

It can, as Bob pointed out, keep some history of files you changed.. but not as neatly as Time Machine does it.

Just the same for most people CCC is far and away the better backup. You can rely on it.. a backup you cannot rely on is almost useless.

Unfortunately due to the failure of Time Machine to backup to network targets. We seem to end up with TM using a local disk and CCC using the Time Capsule.. this is actually the wrong way around.. CCC works far better to a local disk because it can produce a bootable clone.. that means if the internal disk in your computer fails.. the backup on the external drive can be used directly.. and that is ultimately the best test of a backup.. boot from it.. make sure all your emails, photos, iTunes etc are intact and working..

The problem is Time Machine has to rebuild the boot disk to do this which can take several hours.. so is rarely if ever tested. People can then discover TM wasn't backing up certain files.. folders.. messages, emails etc.. and rebuilding the disk is never easy.. whereas the clone is near instant.

What I did is split the external USB drive to two partitions.. I use CCC once a day on one.. and TM at default settings on the other partition.. I also use TM to whatever network target I am testing at the time.. that way I am unlikely to lose files. Time machine to network target fails constantly.. but in this setup it is ho hum.. wipe, rinse and try again.