November 10 2010
I recently had a question from an administrator looking for a way to prevent users from clicking on hyperlinks in Outlook. He doesn’t care if users copy the URL and paste it into a browser, he just doesn’t want them clicking links in Outlook.
Links in the junk mail folder are unclickable, but you can’t block urls in other folders in the same manner. However, you can take advantage of a fairly common problem to make the links unusable.
While most users want to fix the “This operation has been cancelled due to restrictions in effect on this computer.” error, you can force this error in Outlook (and other programs) by editing a registry key.
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\htmlfile\shell\open\command and rename or delete the command key and when a link is clicked in Outlook, the user will receive an error message.
(I renamed it HKEY_LOCAL_MACHINE\SOFTWARE\Classes\htmlfile\shell\_open\_command)
For more information on the ‘Restrictions in effect’ error and solutions, see http://slipstick.me/restrict