I also have an issue with MC18 build 189 using HDHomeRun Prime. The three tuners show up under DLNA and I'm able to load channels, program guide, etc. under Devices --> Television for this device. This is a lot more than I was getting under previous builds. However, when I select a channel and hit WATCH, MC18 crashes every time. It brings up a black display with a message to move the courser to the border for menu, but then it crashes without doing anything. I'm able to use WMC without any issues.