Various reasons can cause Dropbox's sync to stop working, such as client error, firewall blocking, incompatible bad files etc. Restart Dropbox and restart the computer. Check the Dropbox account. Check selective sync.
Why can't I access my Dropbox files?
If you can see the correct files on dropbox.com, but not in the Dropbox folder on your computer, then: Your computer may not be linked to your Dropbox account. The Dropbox app on your computer isn't running. The Dropbox app on your computer syncing correctly.
Why are files missing from my Dropbox?
Your file or folder may be missing for one of the following reasons: It was deleted. It was moved or renamed. It was edited from a linked device, a shared folder, or a team folder.
Where are my Dropbox files stored?
All files stored online by Dropbox are encrypted and kept in secure storage servers. Storage servers are located in data centers across the United States. Additionally, storage servers are available in Germany, Australia, and Japan for some Dropbox Business users. Learn more about how the Dropbox service works.
Why can't I download files from Dropbox?
The reason the download option doesn't appear and is replaced by the "Open" option is because these files are already on your computer. This is because you have the Dropbox software on your computer and these files are already in your Dropbox folder.
How do I force my Dropbox to sync?
On a computer: click the Dropbox icon in the menu bar or system tray, click your profile picture or initials, click Preferences, and then click Account. On iOS: open the Dropbox app and tap Settings. On Android: open the Dropbox app, tap Menu, and then tap Settings.
How do I refresh Dropbox files?
To download or sync updates to your phone or tablet, launch the app and tap a file, or open the Offline files tab. If you don't see a file, pull down to refresh the file view. Learn more about the syncing status of Dropbox files on a mobile device.