Repair Library Error

Multiple Finder popups on my Mac have asked me to authenticate to repair my Library. I entered my credentials for the popups and later restarted my computer (for an unrelated reason). When I log in, the beach ball spins but only the default El Capitan wallpaper loads. The top bar does not load and the dock does not load. Booting into safe mode produces the same result. Is there a Terminal command to fix this? I've seen a few but they require the ability to run Terminal while logged in. I tried reinstalling OS X but sign in repeatedly fails (password is correct). Data is backed up. I love betas.