• Mac: Make sure you see the clouds in the top tool bar and when you click on them that it is says everything is up to date. 
  • Mobile Device: in the OneDrive app, if you are missing a document, pull screen down until you see the refresh icon. If that does not work, then quit the app and open it up again. 
  • Windows: Make sure you see the clouds near the clock on the task bar. When you click to open it should say OneDrive is up to date.
  • Online: If you are missing items in your OneDrive online, you need to go back to your other devices and troubleshoot there first.