I recently installed Ubuntu 18.04 LTS alongside Windows 10 in a dual boot configuration. The installation completed without error and Ubuntu boots up to a login screen. However, when I input my password and log in, there is no gui at all except a mouse on top of a purple background (the same background as the login screen). No keyboard shortcuts work after this login either. Does anyone know how to fix this?
A few of the possibilities:
Boot into your system BIOS and disable the on-board graphics chip-set if you have installed a discrete graphics card.
If this does not help. Boot into Recovery mode Check file system (fsck)
If this also does not help. Boot into Recovery mode, drop to root terminal & Command:
apt update apt upgrade apt install --reinstall lightdm dpkg-reconfigure lightdm
and select lightdm
apt install --reinstall ubuntu-desktop