Issue\Symptom: 

.NET Framework" error message when users click on emails in OL2013. All OL2013 user’s affected, but not Outlook 2010 clients.The issue is not seen if the "MS Forefront Identity Manager Add-in" is disabled.

Cause: 

The "MS Forefront Identity Manager Add-in" is only supported with Outlook 2007.

Resolution:

We were able to resolve the issue by disabling the add-in.Though the add-in in question works with Outlook 2010..it is still unsupported.

Useful Resources:

Installing the FIM Add-ins and Extensions

http://technet.microsoft.com/en-us/library/ff512688(WS.10).aspx

It references Office 2007 and does not mention any other versions. Most of the support statements are found in forums and not in official Microsoft documentation.

http://social.technet.microsoft.com/Forums/en-US/ilm2/thread/3c29e339-55ea-4ab7-a64d-76f3f1935cde

Thanks & Regards

Rahul Thomas