Please help! Just downloaded Sketchup 2017 but have black dots all over the image. We had the same problem with the 2016 version but manage to uncheck hardware acceleration but there is no option to turn off in 2017.
Used the diagnostic to check we have minimum requirements and all has come back good.
Another possibility, which is ‘on’ by default in several supplied templates, is that your style has ‘show endpoints’ checked. Could that be it? Guessing, without a screenshot though.
In the Styles window, select the Edit tab and the Edges icon, and see if Endpoints is checked. If so, uncheck it and see if that makes any difference.