I have the same problem with Windows 10 and the Kaspersky 220.127.116.114(a). Chromecast works fine from Youtube but I get this really annoying device missing error in the Chromecast extension in the chrome browser version 45.0.2454.93 m. Turning off the scan encrypted settings seems to fix the problem. For those concerned about deactivating this feature it seems that it only has to be off when you load Chrome. Once Chrome is up and running and the Chromecast has been found you can turn encrypted connection scanning back on and the Chromecast continues to work, at least my setup. A bit of a nuisance but workable until the bug is fixed.