I got an "out of storage" message when syncing less than half the allowed 20GB. I finally figured out that this was because of the apparently undocumented Archive "feature." This was only after moving all my local files out of the local sync folder, to find out what was using the space online. (Now, of course, I have to upload 8.5GB again.)
Since the online version does not show the size of folders, is there any way to get an overview of what space is used online? In other words, is there somehow I could have easily seen that, hey, there's this thing called the Archive that you've never heard of or done anything with, and it's hogging all your space online?
And is there any explanation anywhere of what is automatically archived, and why?
Thanks, I had found the first link, but missed the somewhat oblique mention of archiving. When looking at files, you can (in Chrome anyway; doesn't seem to function in Firefox) list them by size. But folder sizes aren't listed, so it is apparently the case, as I first observed, that there is no way to visualize how your space is used.
The second link says "These files are stored on the Adobe servers and do not take up any of your account allocation." Very interesting, seeing as the first link (official) says, "Archived files continue to occupy online storage." Which was the problem I had.
I still think it would be nice to be able to see folder sizes, as in any desktop OS.