The following web site explains why that is:
It appears since Google Chrome has disabled NPAPI and that affects the users who access Citrix Receiver from the web and who use Chrome on Windows and Mac. The web browsers that always prompt them include: Even if they already have Citrix Receiver installed. Our users are constantly getting prompted to download Citrix Receiver, when they are prompted to their username/password from our Citrix StorFront Portal. How to turn off the Citrix Receiver detection and will it kick off users or cause any downtime?
