Bit of a weird one. Users were sending hyper-links to public folders to each other within outlook messages. All opening fine in outlook 2007 sp2. I upgrade a couple of users to Outlook 2010 and the links are now not opening, Outlook is showing a security notice warning. Then prompts to choose the program to open it in, i point it off to Outlook and then it just fails. It seems all other links are running. Has anyone come across this issue with Public folders in 2010 before?