Unable to connect to or Map Network Drives (O365).

Access Denied. Before opening files in this location, you must first add the web site to your tusted sites list, browse to the web site, and select the option to login automatically.

Symptoms: “Access Denied. Before opening files in this location, you must first add the web site to your tusted sites list, browse to the web site, and select the option to login automatically.”

For example, a user receives the error message in the following scenario:

  1. When a user tries to access a mapped SharePoint Online Document library/site from the computer.
  2. When a user is trying to map a SharePoint Online Document library to the computer.

Cause: This error occurs because the SharePoint Online sites are not added to the trusted sites.

Resolution:  

Application Layer (Internet Explorer):

 

 

 

 

Presentation Layer (Operating System (Windows)):