Following AndyMac’s experience above in re-downloading Sketchup today I noticed there’s a link to Sketchup “official” advice on one of the forums.
See: Important Update on a few Potential SketchUp 2017 issues on Windows
Downloads page notice here: Download All | SketchUp
I turned Win10 updates on, let it all catch up after turning it off on 19 May… Sketchup select tool OK after SU re-install…but the test will be over next few days … cold boots and restarts seem to have different result.
So next few days will tell …