I had the exact same problem just today. I was using some blocks in a drawing and adding some text. When I saved as PDF all the text was not shown.
For the life of me I did not see it to start with because I rarely use the layers. When I checked the layers, the one with text was set to "not print".
That worked for me.
AS Glenn asked, Does this happen when you Print to PDF as opposed to Save as PDF?
When you preview the PDF (in Print PDF) does the block show up as blue or black?
I have found Print to PDF messes with my line weights and such if the correct paper size isn't selected, where as Save as PDF just does it correct automatically. Which I know is not your problem, just a heads up.
When you Save as PDF in the options are any of these selected?
Thanks Terry, Glenn, Sarah,
It was the layers issue, so changing the layers for the blocks fixed this. I did this before confirming Sarah's post but will be sure to reset the options if I experience this again. Now I know what to look for.
Glenn, I had tried printing to PDF yesterday and the results were okay but I didn't like the extra steps to get the print in this case. I have a one click macro to save PDF and DXF copies, so don't like to have to do it any other way.
I am always very grateful for the help from the folks on this forum. You all make SW life a much better experience that it might otherwise be. Thanks!!!