I'm trying to create a filtered powerlist that pulls contacts when they have never gotten an email from us before. We have a field in SFDC that keeps track of the last date an email was sent and at default has no data in it. I'm trying to create a filter that says, "Date field is equal to null" but it keeps returning an error that I need to input a date. 





Is this a bug, or is there something I'm missing here?

Edit: I can put a value in like "Run Date" but then would it trigger when it's equal to both run date or a null value? That could result in people getting the email two days in a row, could it not?