If you are getting a popup while navigating through Microsoft Dynamics CRM Application asking you to save Blank.aspx file, following workaround will help you
Please edit the default blank.aspx file in CRM (Sever where CRM is installed) so it contains data. This file is located at My Computer | System Drive | Program Files | Microsoft Dynamics CRM | CRMWeb |_ root. Here you will find the Blank.aspx text file.
Open the file and add some text to the file, for example you can add "Test" to the file (then there would be following three lines)
<% Response.Expires = 1440; %>
<% Response.Cache.SetCacheability(HttpCacheability.Public); %>
Once you have added data, save the file, clear your temporary Internet Files, and do an IISreset. Once this is done go back into CRM to verify that this has resolved this issue.