Open with Windows Explorer is Disabled in SharePoint 2013 or in SharePoint 2010? Well, Open with Explorer works only in the 32-bit version of Internet Explorer! It may not work on Chrome or Firefox.
To enable Open with explorer, Open your SharePoint 2010 or SharePoint 2013 site with the 32-bit version of Internet Explorer, located at: “C:\Program Files (x86)\Internet Explorer\iexplore.exe”
Getting error on clicking open with explorer in SharePoint 2013? Well, Use this checklist to resolve: Open with Windows Explorer Error and Solutions for SharePoint