thanks. that solved my issue. But can i not turn it on again? OR will i ever need to use that one?
Graphics acceleration may only be needed if you are using a 4K monitor.
Many LR users find it is not necessary to have 'on'.
Some find that with it checked 'off' their Lightroom development slows down.
For me it is- "try it and see" Use what is best for you.
An update of your Graphics Card Drivers from the OEM (NOT Windows) may also change what you see.
I got it. Thanks very much for your help.