Well, its been a while from the last tip, so here it goes
I recently switched mail clients, moving from Outlook Express to Outlook. While the latter is more efficient than Outlook Express, I find it annoying that Outlook automatically blocks certain types of attached files. I understand Microsoft is only trying to protect its users from malicious content, but there should be the option to turn this filter off.
Luckily, not all is lost and with a little bit of registry hacking we can allow forbidden files to be accessed. First load up regedit (Start -> Run then type regedit and press the Ok button) and follow this path HKEY_CURRENT_USER -> Software -> Microsoft -> 11.0 (10.0 for Outlook XP and 9.0 for Office 2000 SP3) -> Security. From there add a new String Value and name it Level1Remove. Once that's done enter all the file extensions you want to have access to separated only (no spaces!) by a semicolon (. For example: .mbd;.url;.zip

From there, save and exit and now you will be able to access files that would normally be forbidden. If need be in the future, you can add more file extensions at a later time.