Does anyone else have issues with StartOS HDMI? It'll work right after a boot, but it seems like the OS sleeps or something after awhile and the HDMI won't find a signal when the display is connected.

I have the machine connected to my TV and will periodically switch to that input, but I can't get anything to display unless the machine is hard restarted, which obviously isn't good. Trying to use the keyboard and mouse doesn't help.

The system is running the latest OS.

#StartOS @Start9  

 Most likely this is an issue with the graphics driver. Which ISO did you flash? Many screens will need the "nonfree" ISO to work properly.

May I ask why do you have screen connected? Except for flashing firmware and extremely rare debugging purposes, there is absolutely no reason to connect a monitor. servers are meant to run headless (mno screen/monitor).