Consider the following scenario: You use Microsoft Internet Explorer 9 to gain access to Outlook Web App. In this scenario, when you try to open or preview some messages in Outlook Web App, you may notice Internet Explorer takes very long time to open the messages.
This issue occurs when the content was pasted from the web into the message that you are trying to preview includes many incomplete @font-face declarations.
To resolve this issue on a client computer, install the following update.
Security update information
To resolve this issue, install the most recent cumulative security update for Windows Internet Explorer. To do this, visit the following Microsoft website: