High Sierra problem with Monitor parameters

I recently updated to High Sierra on my Mac Mini. I use a Samsung tv monitor and need to alter the parameters to allow me to see the top / bottom of my output. Prior to the update all worked fine, but now every time my computer "sleeps" it comes back having defaulted to chopping off the top / bottom of the screen image. I then have to right-click on the desktop to get to system preferences so I can alter the Monitor parameters. This is very annoying to say the least.