This is a known issue with Adobe Reader, and it depends on Adobe updating their plugin. Whilst you're waiting for Adobe to fix their plugin, you can disable it and fallback to the default PDF reader in Firefox by following these steps: #Go to ''Tools'' > ''Options'' (or ''Firefox'' > ''Options''). #In the Options window, select the ''Applications'' tab. #In the ''Search'' field, type ''PDF''. You should find ''Portable Document Format (PDF)''. #On the right handside you should find an ''Action'' column. In order to view PDF files in Firefox, choose ''Preview in Firefox''. Did this fix your problems? Please report back to us! Thank you.