When the CRM 2011 web client is opened, it performs a check to see if you have the Outlook client installed. If not, then it will display a notification at the top of the screen that will allow you to install the Outlook client, should you wish:
This can be very annoying, should have not wish to install the Outlook client.
Luckily, you, as the CRM system administrator, can turn this feature off.
Perform these steps:
1) Select Settings, Administration, System Settings.
2) Click the Outlook tab.
3) At the bottom of the Outlook tab, you’ll find an option to turn off the “Get the Outlook Client” message:
4) Set that option to No.
5) Click OK to save your change.
6) Refresh your browser using Ctrl+F5.
7) You should no longer see the Outlook client invitation.