I'm using Eclipse for Windows and autocomplete is giving me white text on white background. Is there a setting I can change to fix this? I've looked around but there doesn't seem to be an answer on the internet. Thanks!

In "Window>Preferences"
then "General>Appearance"
make sure "Use mixed fonts and colors for labels" is turned on.
then ">Colors and Fonts>basic"
"Content Assist Background/Foreground Colors" choose anything you like
Have you tried restoring the defaults in the General > Appearance > Colors and Fonts and General > Editors > Text Editors preferences?