I use gvim as my text editor and the syntax coloring is great except it highlights "errors" and gives it a white background with red font. How do I turn off error highlighting? I find it annoying and don't need it.
The highlight of error messages is determined by the Error and/or ErrorMsg highlight groups. I'm not sure which one you're seeing, so you might as well disable both. You can see how each group is defined by executing, e.g.,
which will show you, in color, a line like this:
Error xxx term=reverse cterm=bold ctermfg=7 ctermbg=1 guifg=White guibg=Red
The easiest way to clear those settings is to execute
:hi Error NONE :hi ErrorMsg NONE
If you never set any colorschemes, I think you can just put those commands in your ~/.vimrc, after any
:colorscheme commands. If you change color schemes, you will need to do something like using autocommands to make sure those highlight groups are always clear, e.g.,
au ColorScheme * hi Error NONE au ColorScheme * hi ErrorMsg NONE au GuiEnter * hi Error NONE au GuiEnter * hi ErrorMsg NONE
The GuiEnter autocommands account for the behavior of Vim when invoked as gvim, which is to defer some color setting until after ~/.vimrc is read and the GUI is brought up.