# Disabling Custom PDF Browser in New Firefox
New version of Firefox contains custom PDF files viewer, which is not as good as the standard Adobe Reader. To restore Adobe Reader as default browser for PDF files:
- Enter "about:config" in address bar. Double-click on "pdfjs.disabled" to set it to "true". This disables the new browser.
- Enter Tools > Options dialog, Application tab, locate "Adobe Acrobat Document" and set it to "Use Adobe Acrobat (in Firefox)". This restores Adobe Reader as as browser embedded inside Firefox.