Upgraded 14.10 to 15.04, desktop fails to load past login screen. I type in my password, hear a failure sound byte, back to login screen. Also can't boot off a 15.04 thumb drive created with another PC. Guest account does same thing. Tried removing all nvidia driver packages, tried messing with .Xauthority, tried using gdm instead of lightdm (failed even worse: no login screen at all).
Tried reinstalling ubuntu-desktop.
Get error code of ACPI PCC probe failed, starting 219 or something like that.
Currently running 15.04 off said thumb drive…on an another PC with AMD integrated graphics, no issues.
15.04 doesn't like Nvidia graphics cards. Please help!
it's you from the future. Here's how I fixed it: I didn't! I re-downloaded the 15.04 image from the Ubuntu website and created a startup "disk" on a USB thumb drive. Today it worked, wehereas it didn't last night :( Perhaps Canonical fixed their image... So I booted from the thumb drive and removed my existing 15.04 and installed a fresh copy! Sure I lost all of my files (VirtualBox, all installed games, etc.) but now Linux works again. Let this be a lesson to you Dustin! Never try and upgrade an Ubuntu OS! Just backup all of your files and do a clean install... just like you used to have to do with Windows!