I've followed every tip i can find on trying to correct this issue, trying to log in, launcher update starts but errors out 'unspecified error' .. fresh install, still nothing...logged in without any problems yesterday...
Are your 2 separate machines in the same network or are using the same antivirus on both PCs? The 'Unexpected Error' can be related to routing / ISP issues of the internet connection or to a blocker from a security program.
If you did not had the issue with the same antivirus before my money would be on the internet connection. Did you restart your router already?