SOLVED: backing up cloud-based files

Starting a new thread, because I’ve found a solution that I think will work …

When I learned here that Backblaze is no longer backing up cloud-based files, I read through the thread and decided to give Arq a try, setting it to ‘materialize’ cloud-based files.

Ran into a problem though - my local hard drive filled up with all the (formerly) online-only files! Dropbox support told me that once a file is downloaded it has to be manually changed back to online-only. And Arq support told me that while materialize “sets a flag” to download the file, it does not “unset” that flag.

I then went to Take Control of Backing Up Your Mac and learned that Carbon Copy Cloner will in fact do a temporary download of cloud-based files, back them up, and then re-upload them to the cloud.

So now I am looking at the following:

  1. Use CCC to back up Dropbox and iCloud to an external SSD attached to my computer.
  2. Use either Backblaze or Arq to back that SSD up to the cloud. Probably Arq Cloud - it gives you 5 Macs for the license, so I can also set my husband’s computer to back up.

I can set the timing of the backups so they run in series, at night.

Crazy, right?

Special thanks to Joe Kissell for writing a book that addresses this issue in clear language, and for a comprehensive enough table of contents that I could find it easily!

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That TOC is one of the main reasons I’m a fan of Take Control books.

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I fear you will never maintain the discipline to do all the manual steps of setting up the external drive and moving it to your husbands computer to do the backups. You’d have to do that once a week or so to keep the backup up to date.

Whatever else you do, i would recommend you use a separate SSD to back up each computer.

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Yeah, they talked about this workaround on MacGeekGab last week.

Keep in mind the BackBlaze requirements to keep an external drive plugged in to avoid the backups of that drive being removed after, I think, 30 days?

Not a bad idea, but that could be expensive. The 4TB Samsung SSD I purchased last September is now over $900 on Amazon. That’s about 4X what I paid.

I used to backup a senior manager, who had irregular hours, using ChronoSync on his MacBook and ChronoAgent on a Mac in our server room. Right now the bundle is around $60.

(The server room Mac was backed up nightly with the rest of our servers.)

Arq released an update today that seems to have solved the problem:

Release Notes for Arq Backup Version 7.42

May 12, 2026

SHA2-256(Arq7.42.pkg)= 6ec7d50a9a4d4c28f083805294a61890c69eccace42eebd9d22ba8f522db62d8

Improvements

  • Significantly improved backups of files stored in iCloud Drive and other File Provider-backed locations. Arq now detects “dataless” (cloud-only) files and folders during backup, downloads each one (only if new or modified since last backup), and asks the OS to evict it back to dataless state after the backup completes. Both the modern File Provider extension and legacy iCloud Documents containers (under ~/Library/Mobile Documents/) are handled, and transient “Resource busy” errors from the cloud daemon during eviction are retried with backoff.
  • The activity log now records the full object-lock retention window when a backup with object-locked retention starts.
  • pCloud uploads are now additionally verified by fetching the file’s checksum from pCloud after upload and comparing it to the expected value. This was added after a case where pCloud failed to save all bytes of a file; the post-upload checksum check (suggested by pCloud support) confirms pCloud has received and stored the file correctly.
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my husband doesn’t use cloud storage, so I’m just putting him on the Arq license. good point, though!

Blockquote
I fear you will never maintain the discipline to do all the manual steps of setting up the external drive and moving it to your husbands computer to do the backups. You’d have to do that once a week or so to keep the backup up to date.

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