VERIFIED SOLUTION i
Upgrading from earlier to later release of EngageOne Server 3.X, takes more time than expected.
This could be caused due to huge data (in GB's) residing in '<..>\server\batch\work' directory.
ResolutionUPDATED: September 20, 2018
Ensure to delete the content of '<..>\server\batch\work' directory, before upgrading i.e launching 'install.exe'.