I forgot to add that I can open online pdf files but not the ones stored on my pc.

What default pdf viewer do you have installed?

I had none as I only used firefox. I recently installed adobe acrobat though.

mateokross said

I used to be able to open pdf files on the browser but can't anymore. Whenerver I open one a grey tab opens up and the pdf is redownloaded.

mateokross said

I forgot to add that I can open online pdf files but not the ones stored on my pc.

Do you mean, it gets downloaded again from the original source website, or instead of showing the PDF, Firefox gives you the dialog to Open or Save the file?

Does the saved file open normally in Adobe Reader (or Acrobat)?

Oh wow it just fixed itself. I tried opening a file with the internet off to check if it was redownloading the pdf from the original site or creating a copy and it just worked normally. It used to give me the open or save dialog or save it directly depending on the setting in firefox.