How to Unblock Blocked Attachments in Outlook

I seem to get sent alot of notifications informing me that an email has been sent to me but has been blocked by Outlook because it has an attachment of a certain file type.  Apart from being incredibly annoying, it also seems a tad paranoid..  so here's how to get round that.

Click Start -> Run, Type "regedit"

Now locate HKEY_CURRENT_USER\Software\Microsoft\Office\<VERSION>\Security then add a registry string value in that folder called "Level1Remove" and add the extensions you want with leading dots and trailing semicolons like:

.pst;.rar;.mpg;.avi   etc

(Substitute the appropriate version numbers for your installation, 12 is 2007, 11 is 2003, etc.)

and problem is solved.