I get an error message that Windows System Restore failed?

Not sure why Walter's suggestion was accepted as a solution.  He did point us in the right direction.  But here are more specific instructions on how to edit the Windows Registry.   I posted this solution on Page 10, 01-18-2021 08:36 AM.   This seems to work well.

1. Start "Regedit"

2. Navigate to 

           HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\BackupRestore\FilesNotToBackup
3. Add a Multi-string Value with the Dropbox directory

     a. Right-Click in the window on right-side

    b. Select New

    c.  Select Multi-string value
4. Give the value a descriptive name, like "Dropbox"
5. Double-click the value to open the value editor 

6.  Enter the following string:   %UserProfile%\Dropbox\*.* /s

       (NOTE: This means to ignore all files inside the "C:\Users\{yourusername}\Dropbox" directory and Subdirectories.)

7. Press ENTER

8. Click OK to close.

9. Now, navigate to: 

        HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\BackupRestore\FilesNotToSnapshot

10. REPEAT the above steps 3 thru 8 for this key.

11. Close Regedit

Then, to test if it works, 

1.  Create a System Restore Point

2.  Try to System Restore to the point you just created.

Good Luck & Best regards,

Jacob