Hi paolovalli, if you check the Downloads list in Firefox using

menu button > Tools > Downloads

does the file have the expected .pdf file extension on the end of the name?

Or does the file never download at all?

Hi jscher The files are. jpg files Firefox simply doesn't open them or download them "the file has an invalid format" This only happens on my android phone, the files open fine on my pc running FF.

If a PDF file is being saved with a .jpg extension then it probably will be launched in the wrong application and be considered a corrupt image. I don't know why the extension isn't .pdf for those. Does this occur on all sites or only on particular sites?

It happens on any website where I need to view pdf files from. Bank, credit cards, even my e-pay slips. All pdf files, which chrome has no isuue opening. I'm beginning to think that a complete reinstall is the only solution. Thank for looking into this btw.