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Can't get Firefox to remember my pdf preferences (always asks "What should Firefox do?") [Big Sur]

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Hi guys,

I've been trying for a couple weeks to make the switch from Chrome on Big Sur but am having trouble ironing a few things out. I work in research and view a ton of pdfs, so I like them to (1) open in browser, and (2) specifically, open in a new tab. I haven't been able to get Firefox to do these things.

For (1), I get the "What should Firefox do with this file?" every time I download a pdf from Researchgate (even the same exact pdf). I select the options in the image ("open with Firefox (default)" and "do this every time." But it shows me the popup every time. I've gone to Preferences->Applications->PDFs->Open in Firefox but the behavior persists.

For (2), I'm at a loss - when I open downloaded pdfs, they always open in a new window. I don't even know if it's possible to get them to open in a new tab, but it would be nice and save me a lot of time.

Thanks in advance if anyone can point me in the right direction!

Hi guys, I've been trying for a couple weeks to make the switch from Chrome on Big Sur but am having trouble ironing a few things out. I work in research and view a ton of pdfs, so I like them to (1) open in browser, and (2) specifically, open in a new tab. I haven't been able to get Firefox to do these things. For (1), I get the "What should Firefox do with this file?" every time I download a pdf from Researchgate (even the same exact pdf). I select the options in the image ("open with Firefox (default)" and "do this every time." But it shows me the popup every time. I've gone to Preferences->Applications->PDFs->Open in Firefox but the behavior persists. For (2), I'm at a loss - when I open downloaded pdfs, they always open in a new window. I don't even know if it's possible to get them to open in a new tab, but it would be nice and save me a lot of time. Thanks in advance if anyone can point me in the right direction!
Attached screenshots

All Replies (1)

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Welcome! Firefox will follow your instructions on the Settings page for Portable Document Format (PDF) -- more info on how to set that in View PDF files using Firefox’s built-in viewer -- if two conditions are met:

(1) The server sends Firefox this header:

Content-Type: application/pdf

If the server sends a different content-type, Firefox usually won't match it up with the saved instructions for application/pdf.

(2) The server does NOT send Firefox this header:

Content-Disposition: attachment

This triggers the download dialog. Every. Single. Time.

This second behavior appears to be the issue with your example file.


I have an add-on to work around these two problems. You can install it from the Mozilla Add-ons site:

https://addons.mozilla.org/firefox/addon/content-type-fixer/

To activate it, click its Zzzz button on the toolbar to wake it up. That should take care of #1 automatically. To solve #2, click the button again and in the Content-Disposition Override section of the menu, click "Follow my settings (inline)".