Hi @makesgood,
Do you have Nvidia graphics driver on your primary machine?
Is Nvidia ShadowPlay/screen recording currently active?
If yes, please disable it, reboot then try again with spacedesk.
If problem still persist, please send us the following info:
Primary Machine
– operating system (Windows 8.1/10)?
– graphics adapter (AMD/Intel/Nvidia)
– network connection type (wired/wireless/USB tethering/WiFi Direct)
Secondary Machine
– Viewer type (Android/iOS/Windows/HTML5)
– network connection type (wired/wireless/USB tethering/WiFi Direct)