Do either of the following:
If the COM add-in you want is not listed, you need to add it to the Add-ins available list. Click Add, click the add-in (.exe or .dll file) you want, and then click OK.
To remove an add-in, clear the check box next to the add-in you want to remove, and then click Remove.
Add or remove an Exchange Client add-in
On the Tools menu, click Options, and then click the Other tab.
Click Advanced Options, and then click Add-In Manager.
Click Install and then double-click the extension configuration (.ecf) file you want.
Click OK.
To disable an add-in, clear the check box next to the add-in, and then click OK.