If you order off from Staples.com and own the Brother MFC-790CW, be careful.
We regularly use Staples.com as a reference site for what cartridges go to what printers. However, they have some miss information on the MFC-790CW. They list the LC61 standard Brother cartridges, as well as the high capacity LC65 packs. (link is here) So, after seeing that, I ordered the LC65 for the customer, which is a better value. Customer came back in two days later and asked if I could install it cause he couldn’t. Neither could I, it didn’t fit.
I refunded his payment and then started looking. I went to Brother-usa.com and decided to look on there. Sure enough, the MFC-790CW only takes the LC61 cartridges (See Here).
So as a reminder, the LC65’s will NOT work with the Brother MFC-790CW, only the LC61.