There is a workaround:
Open starcraft, then wait for the loading bar. Now open command line and paste this:
ipconfig /release & ping -n 2 127.0.0.1 & ipconfig /renew
Then the bar should disappear and there you go.
Credit goes to: https://eu.forums.blizzard.com/en/sc2/t/sc2-wont-launch-right-awaylong-loading-bar/830/23