Weird Time Machine behaviour

I’m experiencing a few issues with time machine:

  1. Time Machine backups seem to take a long time. The initial backup was surprisingly quick, but now, backups that are just a few Gb are taking quite a while.
  2. On that note, for the last few backups, Time Machine has backed up quite a lot of data but I haven’t added anything new to my Mac. Not sure why it’s backing up 4Gb when I’ve barely made any changes.
  3. Despite starting a fresh Time Machine backup the other day, the “Cleaning up” phase takes a very long time as well.

Any tips or advice are appreciated.

On point 1, me too. Just waited ‘forever’ for it to back up 4GB so I could delete some files (safely).

  1. I’ve noticed with my time machine backups that sometimes it seems to fly & sometimes it seems to grind. I think it’s often related to what it’s backing up, file sizes & number of (not just the overall size of the backup). Some times seems to go in phases, be really slow for a few days then pick up pace for a while.
  2. If you’ve any apps that update in the background that might account for it. also, I’ve noticed that around the time system updates are coming out, I think it downloads these in the background, then all of a sudden there’s a 4gig backup happening.

Thanks for sharing your experience. It helps to know it’s not just me. :stuck_out_tongue_closed_eyes:

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I wish Apple had made Time Machine better, rather than getting it to its current stage and leaving it there.

I think the best way to use Time Machine is to set it and then try your best to ignore how long it takes when it doesn’t seem to make any sense that it takes that long and why is it backing up so much?

When I was doing my initial backup it reported that it had backed up like 700 GB of data, which is both impressive and odd because:

  1. My drive is only 500 GB
  2. I had only used about 80 GB

Trying to understand Time Machine will, I suspect, ultimately end in madness, sadness, or both. It’s one of the reasons why I don’t trust it much, but I do use it (both via Time Capsule and a drive that I physically connect to my MacBook Air each night). There are times when it’s the best way to get back a file that you need, so it’s good to have… just don’t expect it to seem logical or reasonable in its day-to-day operations.

I think the long backup times and long cleanup times are due to thinning the backups. The one backup per hour, daily for a month (I forget exactly), the backups aren’t all complete backups, but only what has changed. Juggling the various changes, removing backups but preserving others, takes a while. So the delay in backing up a few gigs today may be due to removing a large backup from a week or month ago.
I don’t know the inner workings of TimeMachine per se, but this is how similar backup systems work.

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BTW - if you want to completely ignore my own advice and keep more of an eye on Time Machine, I’ve written a script for that too, and it will show you the various stages in the menu bar, which can help understand Time Machine a little more, if that is what you want:

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Thanks. Remembered you posted this and was going to go looking for it.

While we’re at it, Catalina doesn’t say how much it’s going to back up.
68.3 gigabytes of how much?