Occasionally, the Dropbox sync icons may not appear correctly on Windows computers. Though rare, this problem can arise if you've recently upgraded to a new version of Windows, or if you've installed new applications on your computer. The files or folders are still syncing—the icons simply aren't appearing.
To fix this issue, reinstall the latest version of the Dropbox desktop application. You can do so by running the installer that's available here. If prompted for your computer’s administrator password, be sure to enter it.
If reinstalling the Dropbox desktop application does not resolve the issue, check here for further troubleshooting steps.