As we often get support cases on this topic, here is a whitepaper link which gives background info and self guidance for troubleshooting:
Brief DescriptionThis whitepaper provides general as well as troubleshooting information on using the Explorer View of Windows SharePoint Services.
OverviewThe Explorer View feature that is included with Windows SharePoint Services and is also available in Microsoft SharePoint Portal Server lets users access files stored in the SharePoint database using the familiar Windows Explorer interface. To the end user, this appears to be a very simple and robust feature. In reality, it is the result of a complex series of interactions between many individual components provided by separate Microsoft products.
This white paper is an effort to accomplish three things:
Top News Stories Are You Integrating Properly? (Information World Review) I will stop harping on about