HOWEVER, Adobe Illustrator is not, repeat is not, repeat yet again is not a PDF file editor. Contrary to some popular belief regrettably enforced by some Adobe marketing wonks back in the late 1990's, PDF is not the native file format of Adobe Illustrator.Opened a file (PDF) that was created mid last year in Illustrator 2020 (windows) on the same machine that it was created on. A portion of the text was missing although it was visible in the preview window and there was no Illustrator font error. Tried the newest version of Illustrator with the same results. Opened in Acrobat Pro and it was fine and the print was complete. Attempted to edit the missing text with no success. Placed the document in Illustrator, text was visible but did not print. When the file was created I did use OTF fonts but the missing part was placed from a previous document and I may have not used OTF fonts for this portion.