Time Machine not working with Big Sur

onetoone wrote:

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.

First, I don't know if "most" drives are portable. But the fact remains, if you take a portable drive with you that has a Time Machine backup and data and it fails, wherever it happens to be located, you lose both the backup and the data.

Kerry_Lee wrote:

I've heard many people are having problems with Big Sur. Good luck!

of course you've seen lots of people with issues here. this is a SUPPORT forum. people are here asking for suggestions on how to fix things. nobody posts here just to say "everything on my mac is nice and rosey" :)

Original poster here. I have yet another phone session with my AppleCare support person tomorrow. Last week we tried a series of interventions recommended by Apple engineers based on live comprehensive diagnostic testing from the previous phone session. None of those interventions worked, so my support person recorded another post-intervention diagnostic session, and I'll hear results and new recommendations from the engineers tomorrow. It's definitely a Big Sur-related snafoo, although it doesn't affect everyone who upgraded from Catalina. I haven't been able to back up with Time Machine since Oct. 28.

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. I just want to back up my computer to a Lacie external Hard Drive that the Apple Store just sold to me before i bring the computer in for a battery repair the Apple Store says I need.

Is perhaps my MacBook Air not able to handle this operating system. And, if so, why the heck did Apple suggest I upgrade to it?!!!

MyTM works except the list of backup drives is frozen, i.e., you can't scroll through the list. Hence, you can't see the progress of a backup that is more than 2 drives down the list. This problem is new with Big Sur.

TandemBunny wrote:

I can't even get into Safe Mode any longer. The instructions don't work. Not for Big Sewer.

The instructions are different for newer Macs. You need to read the links provided to you, or post a new Discussion. This one has become hopelessly derailed with "me too" posts describing at least six different Mac of varying descriptions including Time Machine configurations that will never work.

You will never resolve your problem by hijacking someone else's Discussion.

Luckily, I had enough room left on my 4 TB external HD to make another good-sized partition using Disk Utility: this time I formatted it in APFS though (as opposed to Mac OS Extended [Journaled], in which the external HD with about 2 TB of my old backups was originally formatted. Now the new partition is working like a charm: the "preparing backup" section takes less than 5 min for about 130 GB! (BTW, I'm using Time Machine on macOS Big Sur; on a Retina, 13-inch 2015 MBP.) The only downside, though, is that you're going to have to do a fresh backup, which is going to eat up a little bit more of your new partition, i.e., depending on the size.

Hope this helps!

Poldy

Thanks to everyone. I haven't been able to back up since the initial November release of Big Sur. I called Apple Support a couple of times and have tried several suggestions I found in Google searches with no luck. I only had Sophos Home disabled. I should have tried uninstalling it but didn't think of it. After doing that, back ups appear to be working fine again. Thanks for the link to Effective Defenses... without 3rd party software. I look forward to reading it.

Me on the other hand has issue with TM where the TM drive keeps dismounting while TM is doing the backing up.

The issue is random; sometime TM works but most times it doesn't. The TM drive in on RAID 0 configuration.

it sais: "Format: Mac OS Extended (Journaled)" , its connected through USB. I dont wanna play around with it, cause i dont wanna loose the data on it . The problem should not be the disk since, as i said, did the back up on dec 2 without problems.

I can open it, see the content, enter the Time Machine, i simply can't back up the data. It says "preparing back up" for hours. ( i ejected it, reconnected it, rebooted the pc, etc ..)

If it doesn't get out of the "preparing data" phase you have two options: 1 - run Disk First Aid on it and hope it fixes the problem and 2 - erase the hard drive and start over. That 's what I had to do as it wasn't backing up and always preparing. I haven't had a problem since.

There is a 3rd option: get a new external HD and start using it.

Apple had me copy the backups to a new drive before erasing my AirPort Time Capsule drive for troubleshooting, so I know you can do that. It took almost a day plugged in directly with an Ethernet cable. I'm not sure if you can start backing up again to those copied backups. I'm starting from scratch. The backups to Big Sur aren't supposed to take as long, from what I've read. I plugged into the Time Capsule directly, and it took about 8-10 hours to backup 538 GB on a MacBook Pro (Retina, 15-inch, Mid 2015).

Working with Apple support I tried to copy my backup folder to a new drive, but it failed. The upgrade to Big Sur ended up costing me a pretty penny because I'd only recently bought the 4T backup drive that now is unusable. I backed up to the new drive starting in the late afternoon, and it finished by 6am the next day. Subsequent backups have been speedy.

Despite Apple Tech support's assistance and diagnostics, I had to give up on the backups stored in the older drive. Nothing they suggested worked--and the engineers were in on it, evaluating the diagnostics several times. I'll have to erase the old drive, reformat it for Big Sur, and eat the coast of the new drive. Going forward I'll alternate backups to the two drives so I'll always have one if the other fails.

I have a MacBook Air 2020, and the original backup problem started when I upgraded to Big Sur.

I have a the same or at least a similar problem. I bought a new MacBook Air coming from a Mid 2012 MacBook Pro and with that I upgraded to Big Sur. My Time Machine Backup runs on a Time Capsule. The initial backup works fine. After that Time Machine starts regularly to begin a new backup but it only starts with searching for the volume and preparing the backup. Thats it, no further backups :(

That's what mine did. The initial backup worked but nothing after that. I finely found the reason the first one worked is I installed the new version of Sophos, as described in the other posts here, after the initial Big Sur backup. If I had not updated to the new version of Sophos, everything would have been fine. Even better if I had uninstalled the old version.