Downloading a Software Update via the built in mechanism is ridiculously slow:

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My internet connection isn't the fastest, but not that slow either. Furthermore, this Software Update seems to be implemented very badly. If there is a problem, any problem, the whole download is trown away and needs to be initiated again from the start:

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Ideally I would like to download the update via the Bittorrent protocol and verify its integrity with a checksum provided by Apple. I doubt that that's possible though. Is there any other way to download software updates for MacOS?

  • Took less than 20 minutes and I don’t have a rapid connection - my kids tell me so :) So you must have some other issue interfering…
    – Solar Mike
    Commented Aug 27, 2021 at 21:35
  • How exactly does that help answering my question? Commented Aug 27, 2021 at 21:51
  • Re throwing away the download... can you imagine Apple having to listen to people about partial downloads eating their precious disk space? Commented Aug 27, 2021 at 22:47
  • You can download updates at support.apple.com/downloads. Apple does not provide any official bittorrent downloads. Commented Aug 27, 2021 at 23:16
  • @SteveChambers Not with Big Sur.
    – Gilby
    Commented Aug 27, 2021 at 23:22

1 Answer 1


Firstly, don't use BitTorrent to get Apple updates. The risk that they have been compromised is too high. You should always get updates from Apple.

Before Big Sur, Apple provided updates for download at Support Downloads. So, download once and update one or more Macs was possible.

With Big Sur, Apple stopped providing downloadable updates. You now have this choice (which you may not like):

  1. Let the Mac download and install the update (2 to 3 GB) on each Mac - as you have been doing. And, yes, you may need to start again if there are any problems.

  2. Download the complete macOS (12.5 GB). Save a copy in case of install problems before using the complete macOS install to update you Mac.

Where to get macOS?

MrMacintosh has a page dedicated to the downloads of complete macOS for Big Sur. Note carefully that the links he provides are all to Apple servers.

The page also includes sha256 digests for each download. As well as a way to check the accuracy of the download, it would also be a way of checking the accuracy if you do choose to download from elsewhere.

MrMacintosh has other useful pages. How to download describes various ways you can download from Apple's servers - many of these are scripts or apps to assist the process. For myself, I use the MDS method.

From the question, I think you have just one Mac to update. If you had multiple Macs there is also Content Caching.

As you have probably realised, the size and frequency of updates has increased with Big Sur. Read Squeezing a thimbleful of update into a ten-gallon can for a thoughtful diatribe on this issue.


For the Big Sur 11.5.2 a checksum on the macOS install application from Apple can be calculated using:

cd .../Install macOS Big Sur.app
find CONTENTS -type f -exec shasum {} \; | sort -k 2 | shasum

[The find and shasum command was taken from Stack Overflow answer]

For macOS install app from another source, the checksum can be calculated in the same way and compared.

As an experiment I found a non-Apple torrent file. The downloaded install app had the same checksum.

But I am not going to use it!

For torrenting to be a viable and safe method, you need a trusted friend with a reliable connection to download the install app from Apple and compute the checksum. And, who will repeat this for every macOS update.

  • Of course I wouldn't trust some some arbitrary bittorent download; that's why I asked for an official checksum to detect a compromised software update. Commented Aug 28, 2021 at 0:36
  • The download for the complete MacOS is more than four times the size of the update. Thus, only after four failed update downloads the complete MacOS download would have been faster. I guess I take my chances with the update... Commented Aug 28, 2021 at 0:38
  • The checksums from MrMacintosh are reliable. But I am not aware of anyone seeding the official macOS to bittorrent. Yes the full macOS is rather large! But that is only way to get a standalone update/install.
    – Gilby
    Commented Aug 28, 2021 at 0:38
  • @user1785730 For interest, I found a bittorrent (from the obvious source), downloaded and compared with one downloaded from Apple. A few folders had different dates, but the contents of all directories and files were identical.
    – Gilby
    Commented Aug 29, 2021 at 3:14

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