User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b12) Gecko/20100101 Firefox/4.0b12 Build Identifier: 40b12 In some circunstances, PDF printer produces output files with strange size and spacing characters Reproducible: Always Steps to Reproduce: 1. Install Adobe PDF printer or "Print to PDF extension" 2. Print any page (even about:home) with Adobe PDF printer or "Print to PDF extension". You obtain a normal output. 3. Restart firefox. 4. Repeat step 2. You obtain a garbaged, ilegible text output. 5. Make printer preview. You obtain a correct printing. 6. Go to about:config and reset print.print_printer 7. Restart firefox. 8. Repeat step 2. You obtain a correct output. Actual Results: Garbaged, legible text in PDF output. Expected Results: Normal, legible, correct characters PDF output. The key of the problem seems to be: if print.print_printer value equals "Adobe PDF" output is wrong, if it is empty (or the key doesn't appear) output is normal.

Looks like a duplicate of Bug 422253 (which itself is a duplicate of a more general bug).