Enable Firefox to Access a SharePoint Site Without Logging In

By default, you will need to provide a username and password for accessing a SharePoint site via Firefox even though you are in the same domain as SharePoint’s.
This does not happen in IE.
To enable an automatic login for Firefox, you will need to configure Firefox to use Windows’s built-in NTLM authentication.
To do so, follow the steps below:

  1. Type about:config in Firefox’s address bar and press Enter key.
  2. In the Filter textbox, type network.automatic-ntlm-auth.trusted-uris and press Enter key.
    You should now see the specified setting appearing in the preference name section.
  3. Double click the preference name (or right click and choose Modify) to modify the value.
  4. In the appearing dialog, enter the SharePoint server URLs (with no tailing “/”) separated by a comma and click OK when done.

That’s all and you are good to go :)