We apologize for the frustration and confusion with the Launcher. A fix is on the way, but for now we've found that the steps below can help. Please note that this fix is only for the Americas - English (US) client.
1) [url="https://us.battle.net/support/en/article/deleting-battlenet-tools-folder-pc?utm_source=internal&utm_medium=support_forums&utm_campaign=BlizzardCS"]Delete the Battle.net folder in C:\ProgramData[/url]
2) [url="https://us.battle.net/account/download/?show=sc2"]Download[/url] and run the online installer (this will not fully reinstall StarCraft II, and will only re-download some data):
3) Install to the existing StarCraft II location.
C:\Program Files (x86)\StarCraft II
C:\Program Files\StarCraft II
Monday - Friday, 8 am - 5 pm PST
This worked for me, thanks, back to the campaign.