A: To disable this security warning dialog, open the Internet Options control panel applet, then click on the Security tab, then click on the Local Intranet icon, then click on the Sites... button. Within the dialog that appears, disable the "automatically detect intranet network" checkbox option and enable the "include all network paths (UNCs)" checkbox option. Then click OK to close each dialog.
This process should force Windows to treat all UNC paths as Intranet paths, which is usually the case. However, this does open you up to security threats from Internet sites if you are able to access them via a UNC path. e.g.
Another method to get around this problem, but without requiring all UNC paths to be treated as part of the Local Intranet, is to disable the "automatically detect intranet network" checkbox, as explained above, but then also disable the "include all network paths (UNCs)" checkbox option, then click the Advanced... button and add the computer name and full DNS host name of the networked resource (e.g. server1.mydomain.com) to the Local Intranet zone list, then click OK to close each of the dialogs. You can also add your whole domain by using a wildcard. e.g. *.mydomain.com
This security warning can also appear on PCs running IE6 if the "include all network paths (UNCs)" checkbox option is disabled and the network host or domain has not been added to the Local Intranet zone list. In such a case, you'll also find it impossible to open an .MDB file within MS Access from over a network share.