The iPhone 5 introduced support for the 5ghz band.  If your laptop doesn't support 5ghz, it's possible MyWi is broadcasting in 5ghz.    If you are associated with a WiFi access point, try disconnecting wifi and then start MyWi.  

Note:
MyWi 6.0 defaults to 2.4 ghz unless it's already connected to a 5ghz WiFi AP.  If it is already connected, in order to prevent that disconnection, it broadcasts at 5ghz.