Time Capsule (APFS) on Big Sur

I had the problem of the "backup disk image could not be created" after upgrading to Big Sur. I tried all the options of rebooting, reformatting the Apple Airport Drive etc to no avail. However when I disabled Sophos the backup completed successfully as before. I just need to configure Sophos correctly when it is re-enabled.

I have seen some reports on other Time Capsule / Time Machine support forums that indicate that.......IF.......the Time Capsule is completely erased using AirPort Utility, that Time Machine will then format the Time Capsule disk automatically in APFS before the new Time Machine backup on a Big Sur Mac will run.

I have not tried this, so there are no guarantees. Try this only if you are willing to erase the Time Capsule hard drive to see if it will work for you.

I have a similar problem...can someone point me in the right direction please?

1. Airport utility shows my Time capsule as being available and attached to the internet
2. Time machine shows the 3TB data disk on the Time capsule as "waiting to backup"
3. Disk Utility does not show the time capsule at all.....?

How do I get it to show the Time Capsule? Problem has only arisen since upgrade to Big Sur........

Many thanks

Many thanks for your help...followed your guidance but still can't get TM to backup to TC...backup fails with "waiting to complete first backup" message.

Not sure what you mean by mounting TC in Finder. I can see TC in Finder, named as Data. Can see no "Disk Images" anywhere......either in Disk Utility or Finder

What is the other way you might like me to consider?

Edit to post above. IF.....you are running any kind of anti-virus applications on your Mac, or any other type of utility that claims to "speed up", "keep", "optimize", etc your Mac, these types of things do not get along well with Time Machine and can certainly trigger new issues with a new operating system like Big Sur.

Have successfully completed the "Factory Default Reset", re-configured to the same network and passwords as before......and TM still fails to backup to TC

Have come to the conclusion the Big Sur has other things buried deep within that are preventing this process from working.....

Let's see if Apple address this in future Big Sur upgrades.....or not. Not holding my breath, but still really unhappy that perfect hardware (TC) is rendered obsolete because of imperfect software.......

Appreciate your help!

Thank you, removing Sophos fixed the problem....an issue which I was advised of on 1st December but overlooked!

Now reluctant to re-install Sophos.....!?

Macs do not need a separate anti-virus application. The Mac operating system provides all the protection that you need.

Post over in the support forums for the Mac operating system to confirm.

Thank you for saying this, John. Fixed my issue.

Thanks for posting back on your findings.

Looking at your screenshot, it also appears that you can now reformat the Time Capsule disk from Disk Utility and choose to reformat in APFS or APFS (Case sensitive) as well as the older Mac OS Extended (Journaled, etc).

Airport utility shows my Time capsule as being available and attached to the internet

So you just erased the TC drive from airport utility?

Time machine shows the 3TB data disk on the Time capsule as "waiting to backup"

Time machine will then be able to create a new backup to the TC disk which is formatted APFS.. NOTE.. this is an image not the underlying disk.

Disk Utility does not show the time capsule at all.....?

Correct. Disk utility can show a Time Machine disk image.. it has never been able to show the actual TC disk which is NEVER formatted APFS. It is fully owned and controlled by the TC firmware. Disk utility can work only with local disks and disk images.. Look carefully at the screenshot above.. the connection is to disk image. Not the disk.

I have highlighted the key parts. And this is only going to happen when the disk image is mounted in Finder. As it will be when Time Machine is actually backing up.

If Time Machine will not allow you to start a backup.. use add and remove disk option.. remove the current TC from Time Machine.. reboot the computer and go to Time Machine Preferences.. now add back the TC disk as target.. if that does not work first mount the TC disk in Finder .. that should enable the backup to work.. if that fails you can do it yet another way.. Just post back.

I explained the other method here.

https://discussions.apple.com/thread/252095046?answerId=253978990022#253978990022

It helped the person there.. give it a go..

NOTE there is a big problem with 3rd party security software like Norton or Sophos. Even some of the firewall products can give trouble.. if you have any of those loaded on the Mac remove it completely.

Sorry but beyond that I am out of touch with what Apple is doing.

Not sure what you mean by mounting TC in Finder. I can see TC in Finder, named as Data. Can see no "Disk Images" anywhere......either in Disk Utility or Finder

The fact you can actually mount the TC in Finder but Time Machine seems to have issues is confusing.

What happens if you try and force the backup to start?

My very strong recommendation is either backup to a local disk.. as that definitely works better.. or to download an alternative backup software like Carbon Copy Cloner and use that.

I again followed your guidance and also the guidance you gave to another user.....sadly TM still refuses to backup to TC.

Read yours and the other comments on this and agree it is shameful that Apple just leaves users in the lurch with regards to their now perceived obsolete hardware, even though until the Big Sur upgrade it functioned perfectly.

Again, many thanks for your help and guidance