Minecraft fails to set user when trying to launch

I downloaded the new version of the launcher. it hangs up at the Mojang screen and the log says the following:
14:04:14 launcher Preparing to launch minecraft client for 1.12
14:04:15 launcher Checking installations.
14:04:15 launcher Minecraft client 1.12 is ready to start.
14:04:15 launcher Starting!
14:04:16 launcher Using default game log configuration client-1.12.xml (outputs XML)

How do I correct this?