When you click a link on an email in Microsoft Outlook, you are blocked from visiting the URL and you see the following error message:

This operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator.

Cause:

HKEY_Local_Machine\Software\Classes\htmlfile\shell\open\command is missing or corrupt in the registry.

Solution:

In Internet Explorer  go into Tools, then Internet Options and set Internet Explorer as the the default browser.

Or

Restore the registry key from another computer, by issuing:

regedit /e outlook-link-fix.reg “HKEY_Local_Machine\Software\Classes\htmlfile\shell\open\command”

A file called “outlook-link-fix.reg” will be created in your home path (eg: “C:\Documents and Settings\User”).

Copy this file to the system with the problem and open it, it should then prompt you, click yes, it will then say it has been imported successfully.

You can delete this file once you’re done with it.

Enjoy!