[MaryFromMichigan]

Hillary only wins the popular vote when she excludes the caucus states of Iowa, Nevada, Maine, Texas, and Washington state.

More info here.
It's quite convoluted, but here is the gist:

And that conclusion? Using these estimates of actual voters in the Iowa, Nevada, Maine, Washington and Texas caucuses, rather than the initial delegate counts, we get a net total Democratic vote to date of 17,607,152 for Obama and 17,504,742 for Clinton, an Obama lead of 102,410 votes – even with Michigan and Florida included.

[cubreporter]

What in the world is her rationale then for going around saying she has the most votes? I think at this point she is quite dillusional and is grasping at straws that are just not there. Pitiful in a way. Not that I care because she is not, never has been and never will be the kind of President who deserves to represent our great country but...it’s almost like an “I’m ready for my close up Mr.DeMille” moment. Tragic but...reality. Thanks for that info. I think that is exactly what Rachele was talking about. I think her campaign staff or those who have the biggest clout are enabling her into something that will never be.