In response to post #11574013. What would be really nice (although I could see being a coding disaster) is to integrate this requirement into NMM. Whenever you click "Download with manager", before this pop-up appears, NMM would check your installed mods to see if those required files are not only already downloaded, but installed. It'd be equally cool if we could have NMM updated to show requirements when trying to install a mod there too - "This mod requires that [x] be installed, but you don't seem to have it installed. Would you like to install that file first?" With the options of course being "Yes", "No", and "Nice try, NSA... but you won't fool me!"