I received an email from Dropbox saying they were reaching out with an update about Dropbox on the upcoming macOS 12.3 release. They said that Dropbox doesn’t have full support for online-only files yet, and that some apps might have trouble opening Dropbox files while they’re online-only. They said though that I would still be able to open Dropbox files by double-clicking them in Finder.
I asked Dropbox Support about it and Support said that such files are identifiable by the download cloud icon. I said that any files I had un-synced didn’t show at all in my local Dropbox.
That was the clue, and Support then told me that the email had to do with the Smart Sync feature and files that are set to Online-only using the feature, and this will not effect files that have been selected using the Selective Sync feature.
“Smart Sync is a feature of the Dropbox desktop app that allows you to make files online-only so you can save hard drive space on your computer. You can choose which files to make online-only or let automatic Smart Sync choose for you.”
I didn’t know that ‘online-only’ files related to Smart Sync. Now I know.
I never use Smart Sync. I un-sync some files manually to save space on my local hard drive, but they are files (mostly images) that I only need to access very infrequently – as in maybe, never.