Why does vertical text appear on my graph, but not print?

This can occur with Prism Mac version 2. Since the Macintosh system can't handle vertical text, Prism has to convert the text to a bit map, and then rotate and print it. If your vertical text is very long, or in very large point size, Prism won't be able to rotate the bit map so won't print the text.

One solution is to use a smaller point size or fewer characters. If you can't do that, break the text into two separate objects. You can use the Arrange menu to align the two.