There was a change to how Firefox 98 handles file downloads. See How file downloads are handled in Firefox. If you have set PDF files to open in an external application (such as Adobe Reader) in Firefox Settings -> Applications, then the PDF file will also be saved to your default Downloads folder. If you set PDF files to "Open in Firefox" then the PDF file should not be saved.

For more information, see these earlier support threads: /questions/1370152 Downloads defaulting to 'Downloads' folder despite settings /questions/1370612 Firefox mishandles action selected for opening files /questions/1371233 Open PDF attachment

See also: Manage file types and download actions in Firefox and View PDF files using Firefox’s built-in viewer.

Hi jdamonte,

You can choose to load PDF from the internet by choosing to Open in Firefox from the Applications section. See https://twitter.com/FirefoxSupport/status/1508447196328472576

Hi, I hope this is not unpolite to write, but I really hate this change and I would love to be able to specify where files I "open" are stored temporarily (that is, in TEMP). I need to open, comment (thus I want to do it in my preferred editor) and save into sorted folders hundreds of pdfs each month, and now I have to also delete them manually from my Download folder, having no way to easily distiguish them from the pdfs I chose to "just Download".

@gkrmbl, there is a preference in Firefox 102 which enables you download to your temp folder. browser.download.start_downloads_in_tmp_dir

WARNING from the moderator team: Changing Firefox pref from the about:config page can sometimes break Firefox or cause strange behavior. You should only do this if you know what you're doing.

Please read Firefox Advanced Customization and Configuration Options to learn more.

@Terry THANK YOU You made my day, and the following years. I was seriously considering changing Browser after 20 years, because I cannot use my Downloads-Folder anymore because it constantly fills with temp pdfs I need to re-open just to see that I can throw them away.