If Google Drive files are not synchronizing between systems or files are not appearing when you view the conents of your Google Drive storage area from a browser by going to drive.google.com, it is possible the system that should be synchronizing the files has lost its connection to Google Drive. Clicking on the Google Drive icon in the system tray should reveal if that is the case. It can be easy to remedy the connection problem, but you may have to wait a fair amount of time before all files are synchronized after you reestablish the connection.
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