VERIFIED SOLUTION i
'<EngageOne_Active_Drive_Path>\temp\master.xml (The system cannot find the file specified)' message is being observed in the Core logs while exporting Delivery Option from EngageOne Admin -
This is a known defect in earlier releases of EngageOne 4.X
ResolutionUPDATED: November 5, 2018
This has been fixed in EngageOne Server version 4.4.7 (4.4 SP7). Therefore, upgrading to 4.4.7 or later release should resolve the problem.