WebClient service does not support Session Cookies

Applies to: Windows 7 EnterpriseWindows 7 ProfessionalWindows 7 Service Pack 1


Consider the Following scenario:

You have SharePoint server(s) deployed that utilize cookies for authentication (Forms Based Authentication (FBA), FedAuth, Claims based auth). 
SharePoint is configured to utilize session rather than persistent cookies.

You have Windows 7, Windows 8, or Windows 8.1 clients that are accessing SharePoint to

- Publish / Save/ Open / Copy Documents to or from a SharePoint server
Open Explorer View to a SharePoint document libraryOpen Explorer View to a SharePoint document library

When doing this you receive errors or symptoms similar to the following:

%Location% is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions. Access denied. Before opening files in this location, you must first browse to the web site and select the option to login automatically.

Your client does not support opening this list with Windows Explorer.

Can't access ''Folder name"

When copying files to/from the SharePoint Server, the copy process appears to hang


This behavior is expected. The current design of Webclient service expects ‘Persistent Cookies’ instead of ‘Session Cookies’ for proper operation.

By design session cookies are not supported to be handed across processes. Therefore the cookies must be persistent for proper operation of Webclient service. There is no plan to change this behavior.


In order to avoid the error described in the Symptoms section, please use Persistent Cookies and set a minimal Expiration time for the Persistent cookie.

Please use the following white paper as a Guideline on how-to configure SharePoint with persistent cookies:

Implementing Persistent Cookies in SharePoint 2010 Products (white paper)

More Information

Persistent cookies are not shared between Internet Explorer and Office applications

Note: Main difference between Session cookies and Persistent cookies are:

Persistent cookies
are stored on the local drive and have an lifetime defined by the expiration date parameter (see Managing Cookies)
Persistent cookies have an expiration date. These cookies are stored in the local users account under Users\"username"\AppData\Roaming\Microsoft\Windows\Cookies directory, and the Users\"username"\AppData\Roaming\Microsoft\Windows\Cookies\Low directory for applications running under low privileges.

Session cookies
are stored in memory and can be accessed only by the process that created them.

A session cookie can only be used by the process requesting it  whereas a process is a container for a set of resources
used when executing the instance of the program.


RFC 2109  http://tools.ietf.org/html/rfc2109
RFC 2965  http://tools.ietf.org/html/rfc2965
RFC 6265  http://tools.ietf.org/html/rfc6265  

InternetGetCookie http://msdn.microsoft.com/en-us/library/windows/desktop/aa384710(v=vs.85).aspx
Cookie reference  http://msdn.microsoft.com/en-us/library/windows/desktop/aa384321(v=vs.85).aspx
Managing Cookies  http://msdn.microsoft.com/en-us/library/windows/desktop/aa385326(v=vs.85).aspx

Windows Internals Book, 6th edition 
Chapter 5 Processes, Threads and Jobs