Webmail problem

[BaldBoy]

Which is the Scalix release you are working on ?
Is the Scalix's webmail url address listed in the Trusted Sites of IE ?
Which is the security level of your IE for Trusted Sites ?
Do you notice any yellow shield in the bottom bar of IE ?

[BaldBoy]

Any antivirus on the client (we had similar issues with AVG which loaded a BHO to scan links and websites before they're actually browsed) ? Are there plugins installed on IE such as toolbars and other bloatware ?