Does your Windows user name begin with a "u" a "t" or an "r", or one of the other escape characters shown here) ?
… or does it have a Unicode character with a diacritical mark in it?
Looking back at some of the older threads of people having this same issue …
One common culprit is a corrupted Windows User profile. As I had said then, one quick way to test is to create a new user named “Test” (or whatever), log out of your normal user account, log into the new “Test” account and attempt to load SketchUp.
If you cannot get this working, I would suggest opening a support ticket via the website.