Problem: The form link in an email notification is meant to open in the InfoPath client application but instead it opens in a Browser.
Solution 1: Go to Form Library > Form Library Settings > Advanced Settings and change the option for “Opening documents in the Browser” to “Open in Client Application”
Solution 2: Log into the Farm, open Central Admin > General Application Settings > InfoPath Forms Services and uncheck the option to Render Forms in the Browser.
Solution 3: Open Site Actions > Site Settings > Modify All Settings. Under Site Collection Administration, click Site Collection Features and Activate the “Open Documents in Client Applications by Default” feature.Contact Me link in the top menu.