Dropbox folder shows as 0kB when using Time Machine to back up on an external drive.

Hey Reinke, let's jump right into this!

As a first step, can you check and confirm if your content is syncing as available offline before you backup your folder using Time Machine? 

Also, if you simply try to copy an example folder from within your Dropbox folder to your external drive, without using Time Machine do you notice the same behavior then? 

Let me know more, and we'll take it from there!

Thank you! Yes, the data is also stored directly on the iMac ("offline"). As long as the hard drive with the Time Machine backup is connected to this computer, I can see that the backup is performed correctly, and all the data is on the hard drive. The Dropbox folder is approximately 1.5 TB in size. However, as soon as I connect the hard drive to another Mac, the Dropbox folder is displayed with a size of 0 kB and cannot be opened (while other folders like Pictures, Documents, Downloads, etc., are completely visible as normal). Any ideas for help?

Hey Reinke, when you connect your hard drive on a different device, do you view its contents directly from the drive itself, or do you copy them over to your Mac?

Also, do you get a specific error when you try to open your Dropbox folder? Also, have you tried copying an example folder without using Time Machine, by any chance? 

Reinke wrote:

As long as the hard drive ... is connected to this computer, I can see that ... all the data is on the hard drive. ... as soon as I connect the hard drive to another Mac, the Dropbox folder is displayed with a size of 0 kB and cannot be opened

Could this simply be a permissions problem for the Dropbox folder on the other Mac? It can't be opened and appears as 0 bytes because the user account on that other Mac doesn't have access to the folder?

I ask because, typically, if you don't have access to a folder, you can't open it and since it can't be opened to see the files inside, there's no way to see the size of those files, resulting in a folder of 0 bytes.

Hey, I’d like to revisit this issue since it’s still not resolved. When I connect the hard drive to another Mac, I can open it with a double-click and access the respective Time Machine backups. I can see all the data (Library, Applications, System, etc.).

Under “Users,” I can see the Dropbox folder, but it’s not accessible. The information shows “0 bytes” for 1 folder. I don’t get an error message; I just can’t open the Dropbox folder, which appears empty. On the original Mac, I granted access permissions for everyone (Read & Write).

Could you provide further assistance?

Thank you. On the original Mac, I set the permissions (Read & Write) for everyone, but I can’t change the permissions on the Time Machine backup. I can see all the other data from the original Mac in the backup (Library, Applications, System, etc.), but the Dropbox folder is showing as empty with 0 KB.

Hey Reinke!

Since the behavior of Time Machine is out of our scope, we want to make sure that everything works as expected from our side.

With that in mind, allow me to go back to my last question: Can you confirm that if you simply create a copy of a folder or file on your desktop, or any other location outside of the Dropbox folder, can be opened without an issue?

If so, the other thing we could potentially suggest is backing up the Dropbox folder while the Dropbox desktop app isn't running (if that's possible to do), to see if that makes any difference whatsoever.

To answer your question clearly: yes, I can confirm that. I can open and copy all other data to the new computer without any issues. Only the Dropbox folder is locked. Regarding your second suggestion: even if I stop synchronization, the same effect remains. We also have a second Dropbox account with an old iMac and an older macOS. On that system, we don’t experience this issue; the Dropbox folder can be opened on another computer without any problems. I don’t know if it’s due to the newer versions of macOS, but the problem only occurs on the newer computers.

Hi from me as well, Reinke! Please kindly note that using Time Machine to create a backup of the Dropbox folder is something that’s out of our scope of support unfortunately. 

However, I did also check this with our team in the meantime and one workaround I can suggest is to create a manual copy/backup of the Dropbox folder on the external drive instead.

It is like the issue could be related to how Dropbox syncs files locally. Try checking if the Dropbox folder is being excluded from the backup in Time Machine settings. You might also need to ensure the files are fully synced on the original Mac before backing up see more...