Time Machine not working with Big Sur

1. Ok - for those of you struggling to get time machine to work after a Big Sur update - This is what I've tried and what finally worked for me.
2. Once I had updated my 2015 macbook to Big Sur I re-formatted my external hard drive to APFS - I've always used either G-Drives and Seagate (cheaper) - annoying as I lost all my old bkps - thanks apple!
3. I got to about 880GB of bkps when my G-Drive started making loud noises and either got "preparing backup" or "Time Machine could not backup due to errors" - thanks for the detailed error Apple!
4. I ran disk utility on all my drives including the boot drive in recovery mode. I also left time machine running all night while it "Prepared the backup" - still no joy - at this point I'm tempted to re-install Big Sur - but I can't because I don't have a backup of my user account because my old Catalina backup is no longer compatible! Thanks Apple.
5. I deleted some old large files on my macbook to free up space for the snapshots - still no joy. (Shame as really I wanted to back them up first)
6. Uninstall CleanMyMac X and Sophos (basically any anti-virus stuff) - reboot try again - fail
7. So I bite the bullet and buy a new 6TB Seagate drive (I'll definitely have enough space now!) and configured it as APFS - ran the backup and got to the same point about 880GB then Time Machine starts timing out again.
8. I keep hitting the backup now button for the next 72 hours but still get the - oh so vague - "Time Machine could not backup due to errors" - warning! Thanks for the detail Apple.
9. I decided that either my macbook's hard drive is corrupt or my external drive is corrupt - so I exclude the external hard drive from the backup and by hitting the options button in the time machine preferences and excluding that drive.
10. I still get errors, so this time I exclude my main drive. Bingo! Approximately 10 days after I upgraded I get my first backup but only fro my external drive one. Whoop.
11. Then I read somewhere that some third party Apps not found in the App store can cause Time Machine to fail - So I then go into a process of excluding folders from my my drive on my mackbook, first the "Applications" folder, then my "Systems" folder and finally "User" folder. If I exclude my "User" folder - the backup works! - Great I have a backup of everything except my own stuff!
12. So then I got through and one by one exclude each "User", until I discover my own "User" folder is the one that makes the backup fail. Thanks Apple - surely Time Machine could have told me this!!
13. Then I have a brain wave and decide to try and copy my "User" folder over to my external drive and sure enough the copying fails and I get a very specific error, that says something like "There is a problem with your Photos Library and cannot be copied" - Bingo!!
14. After a quick search I find how to repair my photo library - https://support.apple.com/en-gb/HT204967 and after a couple of reboots I get my first full backup of my laptop!

So to conclude, one of the things to try if your Time Machine doesn't work on Big Sur, if you have space on an external drive - try copying the files over manually first - to see if any of them are corrupt.

It's ironic that it was apple's own software 'photos' was the one causing me all the trouble.

I hope this helps someone and thanks Apple! It's great when it works, but when it doesn't - Arrrrrrrggggghhhhh!!!

Same here. Since upgrading to Big Sur, Time Machine gets stuck on "preparing backup." I let it run all night; no joy. I'm on the phone now with Apple tech support. At least for the agent I'm working with, this problem seems to be a new issue. It may have something to do with the way my external hard drive is formatted. Apparently with Big Sur it has to be APFS format. I have no idea what that means, but I suspect my drive is HPF+ formatted, since that seems to be how the G-Drive Mobile is preformatted. It worked fine in Catalina. Not in Big Sur.

Just got off the phone with AppleCare support. They did a whole lot of diagnostics and will get back to me in a few days. If there's fix, I'll share it here for those of you who are also having trouble using Time Machine in Big Sur.

this is interesting..... I tried to copy files to the AFPS Time Machine Volume and could not... Here's why:

..Note: The entire APFS disk is reserved for Time Machine backups. If you want to store files other than the Time Machine backup on the same physical device, use Disk Utility to create an additional APFS volume on the disk. The two volumes then share the available space.

I did that and now have two logical volumes. Works fine.

Boot into Safe Mode by booting with the Shift key held down and check there to see if the problem persists.  Reboot normally and test again.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

I'm not surprised. There is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This user tip describes what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community   

Permanently uninstall any of those types of apps according to the developer's instructions and never install again.

I've been fighting with this for months, and finally found the cause (at least in my case): I'm running Sophos anti-virus, and this is a known incompatibility with their software and Big Sur which they have documented:

https://support.home.sophos.com/hc/en-us/articles/360051251412-Support-for-macOS-11-Big-Sur-

Here is the full description of the problem from their website:

"Time Machine backups to NETWORK locations (Time Capsule, NAS) are currently failing when Sophos Home is installed on Big Sur macOS 11 - Users will see a message reading "Time Machine couldn't complete the backup - The disk is already in use" This does NOT affect local backups, or backups to external devices/drives. 

This issue is currently under investigation by our development team. As a workaround, run the backup in Safe mode or use an external device to backup to. We expect this issue to be resolved by March of 2021."

I got a different error message (several of them, in fact), but otherwise this matched my problem description. In order to solve this, I had to completely uninstall Sophos. Disabling it wasn't enough. Hopefully they get it worked out, but in the meantime, I'd rather have backups than anti-virus (I'll experiment with other AV solutions).

Hopefully this helps someone else!

MARCH 28TH - TIME MACHINE ISSUE,

What worked for me after upgrade from Catalina to BigSur 11.2.3

After several tries to use my previous Time machine backups or update them

I stumbled on what solved MY problem. YMMV.

A) https://support.apple.com/en-us/HT208050

Use zsh as the default shell on your Mac

Starting with macOS Catalina, your Mac uses zsh as the default login shell and interactive shell. You can make zsh the default in earlier versions of macOS as well. Goes on with link to instructions

B) Followed instructions carefully to change the default login shell to zsh !!!!

C) Shut down and rebooted computer ( I use a Mac mini (2018) 3 gz process 8 gb )...

D) ( I use 3 time machine backups - 1) Networked older 2014 mac mini, 2) an OTG solid state USB, and 3) an old WD MyBook media USB connected disk )

E) Plug in or network load each disk one at a time, run Disk Utility first aid on that disk - may take a while depending on each disk

F) AFTER each is " repaired " using Big Sur version of Disk Utility then mount/network to connect each disk one at a time

G Open time machine - select Enter time machine- backups should be available.

H) Then select Back Up Now .

The above sequence from E) on worked for me on all three different Time Machine disks

Other than having to re authorize a few applications- My upgrade to Big Sur took a few hours but went smoothly ( Used Ethernet connections and not wi- fi )

Well, I tried pretty much everything that looked useful from the discussions here, but nothing worked UNTIL:

(I had two backup drives for Time Machine that I alternated, both that had worked until December 10th, which was when I upgraded to Big Sur 11.1. (Originally my backups had been working with Big Sur 11.0 from mid-November, and with 10.x systems before Big Sur).

Both of my original external drives were encrypted with FileVault, under Mac OS Extended (Journaled, Encrypted). One is a 1TB SSD (Sandisk), one is a 8TB HD (Seagate Backup Plus for Mac).

Note that the Time Machine interface for restoring files seemed like it was still working, it's just that I couldn't do any new backups.

Got that same endless message, "Preparing Backup"... didn't matter if I waited 10 hours, it stuck there, didn't do anything, with either drive.

Gave up and copied all of my backups from my 1TB drive to my 8TB drive (which took about 10 hours or so, an overnight job).

Reformatted my SSD using Disk Utility to be the new APFS (Apple File System, Case-sensitive, Encrypted) format.

• (To my understanding, although it's certainly not clearly explained anywhere, encrypted disks replace the need for FileVault...).
  • Turns out I may not have needed to use Disk Utility because when adding the disk back to Time Machine (after deleting it from Time Machine in its prior instance), it asked me if I wanted to format it, which I did.
  • It's OK, formatting the SSD only took 2 or 4 minutes.

Did a backup, it did the whole 150GB of user data that I don't back up elsewhere to the (now APFS) SSD in less than 90 minutes.

Tried the Seagate (8TB) MacOSExtended drive again, in case somehow Time Machine got freed up/unstuck. No luck.

So, if you are in my shoes the solution is simple:

• wait until apple fixes the bug that stopped Big Sur from working with the traditional MacOSExtended drives, go naked on your backups
• reformat your drive to APFS and start backing up like normal. (and lose all your old backups in the process unless you have somewhere you can copy them off to like I had...)

Good luck!

Is your Time Machine drive a SSD or a rotational drive? I use a rotational drive and it is formatted OS X Extended (journaled) and runs fine with Big Sure.

How much free space do you have on your boot drive? If not enough to let it create a local snapshot TM stalls out.

MarkChekal wrote:

I updated my 2015 MacBook Air to Big Sur.... and now, Time Machine does not work. I go to open it and it opens multiple windows and freezes.

By it do you mean the Time Machine app? Are you using the TM menu in the menu bar?

How is the LaCie drive formatted? I should be formatted OS X Extended (journaled) with a GUID Partition Map.

Since you haven't been able to get the first backup on the drive launch Disk Utility, select the top level of the drive in the sidebar and erase with these settings:

Then try backing up again.

Do you have any files on the TM boot drive in back-ups that are not on your boot drive and any drives your've backing up?

If not then erase the drive and start a new backup on it. I had the same problem with very long "preparing" so erased and started over from scratch. Haven't had a problem since.

I have a 6 GB rotational drive from OWC that's formatted OS X Extended Journaled and have no problem with Big Sur.

However, I did have a problem with the drive in Catalina experiencing the same "preparing backup" that you did. I eventually had to erase the drive and reformat the same. It's been running without problem since.

I didn't have any files on the TM drive that were not on my boot drive so I don't lose any files in the process.

onetoone wrote:

I did that and now have two logical volumes. Works fine.

Yes, that works. However, it's not the best idea to save data on a drive used by Time Machine because if the drive fails (and they will eventually), you lose both your backups and your data.

most backup drives are portable so this ability allows you to put a few files on the drive and take the drive with you,, anywhere. not really meant to be used an extension of external storage, just a temporary convenience.. of course a thumb drive gives the same ability.