@ItsKinsja@FortniteStatus I have different Windows 10 user account on the same PC. That account has a different Epic account. I updated Fortnite there, then switched back to my main Windows account and Fortnite worked.
@ItsKinsja@FortniteStatus I mean another Windows user account on the same computer. I have three Windows 10 user profiles. I logged into one of the other profiles, updated Fortnite, then switched back to my main profile and was able to play.