Symptom:

• You have a page like http://www.mydomain.com/default.aspx.  When someone visits that page, the URL in their address bar changes to:  http://www.mydomain.com/XXXXXXXXXXX/default.aspx or http://www.mydomain.com/(A(XXXX)S(XXXX)F(XXXX))/default.aspx

Resolution:

• You have enabled cookieless sessions in your web.config file.  Please refer to the following Microsoft Article on this:

http://msdn2.microsoft.com/en-us/library/aa479314.aspx