Fix Google Drive not Synchronizing all Files

How to get Google Drive to sync required files and folders

The following steps are what eventually worked for me to get all my required Google Drive folders to sync to Windows 10. In the steps below you’ll be reinstalling Google Drive to Windows and then syncing all your files and folders. Follow the instructions below:

1. Quit Google Drive. To do this alternate click the Google Drive icon in your taskbar and click Settings. Then click Quit Google Drive.
2. Uninstall Google Drive from Windows.
3. Rename the Google Drive folder in Windows Explorer (I renamed mine to Google Drive Old).
4. Install Google Drive.
5. Follow the setup instructions to install Google Drive.

Google Drive will now sync all selected files and folders to your local PC.

If you have a large amount of data stored in Google Drive then this synchronize will take quite awhile and will use alot of bandwidth.

Source : Google Drive Customer Service Number