I think that you are focusing on the wrong thing. Explorer is not the problem in the sense that you don't need to wait until explorer loads nor to map the drives before explorer loads. Something else is going on. You need to provide more information. Is this on windows 7, xp, is this on new machines, old machines, does the script run at all when the drive mapping fails, are your drive mappings persistent. Ignore the issue of having to restart explorer. Explorer should not be the problem, but without more information its kinda hard to say what the problem is.