When attempting to open up a Microsoft Access database file on a network share, I received the following error message:
"Microsoft Access cannot open this file.
This file is located outside your intranet or on an untrusted site. Microsoft Access will not open the file due to potential security problems.
To open the file, copy it to your machine or an accessible network location."
Microsoft's Knowledge Base articles 303650 and 810582 describe this issue, along with many work-arounds. Unfortunately, none of these worked. The share was a drive letter mapped to a FQDN (e.g., \\myserver.efflorescent.org\myshare); apparently an IP address or in some cases even just the NetBIOS name can cause this problem.
Solution: Follow the steps in MS KB 303650. If these still fail to work, log on to the machine with a local account with administrative privileges. Go to the Internet Options setting in the Control Panel and (if not already done) set the Local intranet security zone to the default level of Medium Low. Then, click Sites, Advanced, and add the server FQDN and IP address to the list of allowed sites (e.g., "myserver.efflorescent.org" minus quotes).
For some reason, making these changes as a non-administrator did not work -- at least on the computer I was having problems with. Probably a fluke, but not sure as to why this particular computer was having an issue with things. Resetting the settings as a normal user appeared to work, however the settings would not stay.