What's the exact difference in meaning here?

Question

"I used to dream of you until you vanished."

"I used to dream of you up until you vanished."

Answer 1

There is not a practical difference in meaning here, but "up until" may suggest a more definitive point in time, as in "I used to dream of you ("all the way up" or "right") until you vanished."

Answer 2

I agree with the other expert answer above that there is no practical difference. My reading of the two sentences is that "up until" you vanished is a clearer and more specific description than "until you vanished." If I were choosing between two sentences, I would go with "up until."