As I think this is because of microsoft software related policy, as they support only there own created products like you experienced, they not allowed any third party software for default applications they support.

I don't think that there is other way to change that.

For this you need to have Firefox set as your default browser. This article explains how.

As Chandan_Baba said, this might not work though, as Microsoft have a vested interest in making Outlook open links in Internet Explorer.

That article did not help as I had already tried setting Firefox as default, however this article did fix it Here

Hi Chandan_Baba, I have used Firefox as my default browser with Microsoft Outlook since before Firefox 1.0 and rarely ever had a problem. So while some configurations might have issues, I would look for causes outside of Office itself (e.g., registry corruption).

Note: I only have experience with Outlook 97-2010, not Outlook 2013.

Hey snd 978 ..... This is how you set firefox as browser : http://office.microsoft.com/en-nz/outlook-help/change-your-default-browser-HA001190694.aspx Here change the firefox inplace of internet explorer .

Another way : Set Program Access & Defaults' from add/remove programs. Use the 'custom' pull down and set FF as your default browser

Note : at time of doing Firefox must be closed

Heyjscher2000......nice to see you here !! I'm providing these information based on oulook 2013 ,you are right with your words