They go through the motions of downloading (seemingly successfully) and then they try to install but fail with the helpful message saying "unable to update xxx, please acknowledge" with no help or explanation offered.

I have tried clearing the play store/play services cache and data, cleared the individual apps cache and data. All with no joy... the last "fix" I found through Googling was remove and reinstall... well that has resulted in me now not having one of my apps at all as it won't reinstall either!!

Does anyone have anynother ideas??