A couple of months ago I installed 14.04 and since I did so my screen always bugs out after I type out my password and hit enter. This is what it looks like:

Login screen

It does this for about a minute then it's fine afterwards. The background is always purple and the login box is always white for some reason. I've tried to fix it but nothing has worked.

Desktop

Just recently I have moved from Unity to Cinnamon and in doing so I purged Unity thinking it would fix my purple background issues. It didn't work, so I'm having troubles finding what's messing up the login screen. The desktop looks perfectly fine and I never have this issue anywhere else except for when I log in.

The running resolution is 1600x900 (native res of my Dell Inspiron N7010) and I use Core Processor Integrated Graphics Controller on an Intel Pentium.