I've purchased Windows Download version. I'm at my five max returns, but different email addresses. Can I do one more return for my son's fiance?

No a different email address will not add back another 5 e-files.

The number of e-files is set by the IRS and cannot be changed or increased.  All further tax returns after the 5 free e-files have been used can only be printed and mailed.

Thank you for the quick reply!