Hi to all, I do had the same problem.
I tried almost everything and fail.
Then i solve the problem, in my case i have window 10, and i download a small software to take ownership full access of the 2 folders: program file - sketchup folder and %appdata% sketchup folder too.
Then i open Sketchup as administrator, positioned all my toolbars, save as default template and closed.
And Voila finally all is ok.
here is the video i followed with the link to download.
Youtube Video
Hope it will work for you!