One Monday morning I handed Cowork a folder inside Dropbox and asked it to pull together last month's invoices. The reply was a single line: the file wasn't found at that path.
I opened Finder and there it was. Name, date, everything. And yet, from Cowork's side, it simply didn't exist. I re-granted the folder permission, doubted my settings, and half an hour disappeared before I understood what was going on.
The culprit wasn't Cowork or the permission. It was the state of the file in Dropbox: online-only. If you're stuck at the same spot, here is the order I now follow, from recognizing the symptom to fixing it.
First, check that this is really your problem
Before changing anything, I look at which row of this table my situation matches. If one does, the rest of this article is likely for you.
| What you see | Most likely cause |
|---|---|
| The name shows in Finder, but Cowork says "not found" or can't open it | The file is online-only; no real copy exists on your Mac |
| Some files in a folder open fine, others don't | The ones that open are local; the ones that don't are online-only |
| The folder itself never appears | A wrong folder was granted to Cowork (a different problem) |
| The filename ends with "conflicted copy" | A sync conflict (also a different problem) |
The fastest clue is the status column in Finder. A cloud icon next to a file means its contents aren't on your Mac.
Why "visible" doesn't mean "there"
An online-only file is, on your Mac, a bit like a luggage tag with no suitcase attached. It carries a name and a size, but the contents live on Dropbox's servers and are fetched only at the moment something tries to open the file.
That's where two of Cowork's tools behave differently. A shell command looks at what is currently on the disk. A tool that reads a file directly can end up triggering the download as part of opening it. In my own setup, I've repeatedly seen a path fail in the shell and then succeed through the file-reading tool.
The exact behavior may vary with your Dropbox version and macOS settings, so please treat this as a working model rather than a spec. Still, thinking of it as "a tag without a suitcase" makes the diagnosis much simpler than hunting through permission screens.
The order I check things in
There are three steps, and they're short:
- Right-click the file in Finder and look at its status.
- Ask the terminal whether the contents are really on disk.
- Try a second file in the same folder and see whether it behaves the same way.
For the second step, these two commands are enough:
# Show file flags ("dataless" means the contents are not on this Mac)
ls -lO ~/Library/CloudStorage/Dropbox/Invoices/2026-09_CompanyA.pdf
# Show real disk usage (0B suggests no local copy)
du -h ~/Library/CloudStorage/Dropbox/Invoices/2026-09_CompanyA.pdfIf ls -lO prints dataless, the file is online-only. The exact output can differ between macOS versions, so if you don't see it, combine the du result with the cloud icon in Finder before deciding.
The third step matters more than it looks. If every file in the folder behaves the same, I suspect the whole folder is online-only. If only a few do, I know I'm dealing with individual files, and I can fix just those.
The fix
Right-click the file or folder and choose "Make available offline." Depending on your Dropbox version the wording may differ, for example "Save locally." Dropbox downloads the contents, and the cloud icon turns into a green check.
Then ask Cowork the same question again. In my case, the "not found" message vanished at that point and nothing else needed changing.
There is one caution I'd like to pass along: don't make a parent folder available offline all at once.
Where I overdid it
The first time I hit this, I panicked and marked the top-level Dropbox folder as available offline. The error did disappear. But free disk space shrank steadily, and my Mac felt sluggish until syncing finished. It was not a good trade.
Here is the line I draw now.
Share with Cowork only the folders that have real files on this Mac.
Concretely, I made a small working folder inside Dropbox that holds only what I'm comfortable letting Cowork see, and I made only that folder available offline. Older documents and large assets stay online-only. The surface Cowork can touch got smaller, and two worries shrank together: running out of disk space, and the chance of showing it a file I'd rather not have read.
If you want an additional habit, I'd suggest a quick look at the folder once a week. Files you no longer use can be switched back to online-only, which gives the space back without deleting anything.
What I'd try today
Open the folder you've granted to Cowork in Finder and scan it once for files with a cloud icon. If you find a few, make just those available offline and send the same request again. I started there too, and it was enough to get me moving.