I purchased a Pi for my daughter with a pre purchased OS on a SD. We hooked it all up and started the power. After entering the PW and startx the screen when blank for a few minutes.
Then I got a page of Invalid MIT-MAGIC-COOKIE-1 Key.. then 'giving up' followed by
server error and error in locking autherity file /home/pi/.Xauthority
This is a new Pi being booted for the first time.