All issued certificates are PDF files. Sometimes a program will fail to render them properly --we recommend keeping your software programs up-to-date to avoid this issue. Also be aware that modern web browsers will render PDF files without using any third-party programs --so there is no need to install third-party programs to view/print PDF files.
Some users have had issues on Windows systems using Adobe Reader. These users have had success for these uses has been by doing the following:
Uninstall the Adobe Reader program.
ASIDE: Adobe Reader typically sets web browsers to run Adobe Reader instead of showing the PDF file and it is Adobe Reader --not the web browser-- that gives an error with the file. It is possible to change this setting but it is typically a different set of instructions for each web browser so it is not worth going into such detail here. Instead uninstalling Adobe Reader is and consistent.
Access/Download/Print the certificate (e.g., via the web site).
(Might as well do this when Adobe Reader is not installed.)
And optionally re-download and install Adobe Reader, e.g., if you want it installed.
Re-downloading it is a good idea to get the newest release and bug fixes. Don't rely on a file you already have if it was already giving errors with our certificate PDF files.