That sounds very strange. Why is the resolution involved in that? Here is a default setting for MD and I use it with a 720p camera and I have 1280p also.
There must some changes from default somewhere in your NCS. You say cameras. How many cameras? Can it be a problem with an overloaded CPU? Actually, I cannot even guess right now. Is the installation corrupted? Have you made a clean installation which means also remove all the configuration files in the C:\ProgramData\Moonware folder after running the installation program again and using Remove?