Does anyone know if there is a way to warn you about any overprinting in an Illustrator file beisdes turning on and off the Seperation Preview. It would be nice if the warning came up as you save like if a link is missing or a font is missing?
You mean white overprinting?
There's a plugin for the Mac: see worker72a.com
No there is no warning like that.
View >> Overprint preview is the only safety check (same as clciking the box above seperationsn preview)
or you can select all but the images and then turn off overpint in the attributes panel.
Which version of Illustrator are you using?
CS6 non CC