To save the changes to the sheet sets, complete the following:
Close all sessions of autocad running.
Click Save Changes. It will warn you that it will save the changes back to the DST files.
Civil 3D opens and saves the changes and then closes. You will get a message stating the changes have been successfully saved.
Click OK.
A dialog box displays asking if you want to update the ProjectIndex.xml. Click Yes.
A report displays stating the results of the changes. Note: A common message that will display is for missing plot files, which results from the renumbering of sheets.
Click the X in the upper right corner to close the report.