SOLVED! Dropbox failed to sync after upgrading to Windows 10

After upgrading my Windows from version 7 to 10, I noticed that Dropbox stopped functioning. It didn't get sync.

To solve the problem, this is what I've done:

1. Start Task Manager (Windows Key+X), find "Dropbox". (Press "More details" if you cannot find the app)
2. Right click on "Dropbox" and select "Properties"
3. In the "Properties" of "Microsoft OneDrive", go to the "Compatibility" tab.
4. Check the box "Run this program in compatibility mode for", and select "Windows 7" from the list.
5. Exit your Dropbox and start it again; or restart your computer.

Similar fix also work for Microsoft OneDrive.