My last name has legally changed, and my pharmacy filled my prescription under my old name?

I assume you're a regular and they know you? I had a similar incident happen one time where I went to the doctor and got a script, and they put my middle name instead of my first name like normal. Showed I.D and was good to go. If you changed your name then you should tell them you would like to update your profile. That way you don't run into a newbie tech or a "floater" pharmacist who might not be so helpful. Best of luck.

So they didn't change the computer, what is the big deal. Both names were yours. If it was an alias then it would be a problem. If its important to you tell them about it the next time you go in.