Starcraft used to work fine, until yesterday (2023-03-20). Since I’m not the only one experiencing this, it must be something on Blizzard side.
Anyway, if you’re encountering an “unexpected error” when you press play in the battle.net launcher, you can fix this by clicking on the cogwheel next to the play button. Then go into game settings and tick “additional command line parameters”. In the textbox enter
Starcraft should now work again.
(P.S.: I’m new here, sorry if this is not the right place to put this.)