Firefox Community Forum

I closed a PDF file but can not move it to another folder. Windows says it is open in firefox. I closed firefox and it still says it is open in firefox. I even restarted windows and it still says it is open in firefox. How do I get firefox to close and release the file?

Hi everyone,

After enabling `privacy.resistFingerprinting = true` in `about:config`, I noticed that Firefox’s built-in PDF viewer (`pdf.js`) is always displayed in **light mode**, even though my system and browser themes are both dark.

I understand that RFP forces `prefers-color-scheme: light` to prevent fingerprinting, but this also affects internal components like the PDF reader. Unfortunately, the PDF viewer doesn’t provide a manual dark mode toggle.

Is there any **official or safe workaround** that allows keeping RFP enabled while still having the PDF viewer use dark colors?

Thanks!

On one PC, pdf files [Type of file : Firefox PDF Document (.pdf)] display with a PDF icon but on a second PC, pdf files [Type of file: PDF File (.pdf)] display with a Firefox icon.

What changes are needed to have pdf files display with a PDF icon on the second PC?

I am a Dropbox user. I have until recently been almost strictly a Google Chrome user. The PDF seamless behavior I have been seeing in Chrome is like this: 1. If I click on a search engine result for a PDF, I see the PDF opened in the browser. 2. If I click on Download at Dropbox, the PDF is downloaded to my PC.

On installing Firefox, the behavior I saw was like this: Whether I clicked on a search engine result or Download at Dropbox, I saw the PDF opened in my browser.

When I changed the Action for Portable Document Format (PDF) (application/pdf) and Portable Document Format (PDF) (application/binary)to "Save File", the PDF downloaded to my PC. But so did search engine links.

I seem to have fixed the issue by making my settings like this: 1. Action for Portable Document Format (PDF) (application/binary) to "Save File" 2. Action for Portable Document Format (PDF) (application/pdf) to "Open in Firefox"

Fingers crossed. ??? I was wondering why it wasn't set up this way on installation.

I am a magazine editor right on deadline and as my Firefox inisted it must be updated I endeavoured to do so and now it will nor allow me to open up and forward any pdfs.Please help.

I'm trying to use Firefox to fill out my tax forms, but while I can save them and view them with Firefox, they're blank when I open them with Adobe or print them. This is, to say the least, NOT USEFUL. What is happening?!?? I'm using Win10 and the latest version of Firefox, and I tried it on an old Mac with the latest version of Firefox as well.

I have a question about using Firefox PDF Editor. I copied some text from a PDF document that is on my computer, by highlighting the text and then hitting Ctrl+C. The text copied onto my clipboard OK. Then I opened a blank PDF document in the Firefox PDF Editor and tried to paste that text into the blank document, but I wasn't able to do so because when I right-clicked on the blank document and then clicked on "paste", nothing happened. This apparently is because the word "paste" is faded-out in the drop-down menu (i.e., it does not appear in prominent bold print). Google's Artificial Intelligence seems to indicate that the technique I used would work (see screenshot which I've uploaded). But it didn't work, so can anyone please tell me how can I paste text into that blank document?

Hi Firefox Team,

Why suddenly today there's no PDF preview for all PDF file sent or received on browser (i.e whatsapp web) Attached latest screenshots

Please assist.

Regards, Novie

I am using the FireFox PDF Editor to annotate a PDF, however, no method of me saving the document (whether that is save as, or save as PDF) will allow me to save any annotations on the document. If I try doing save as PDF, the preview shows up as blank sheets of paper, when I click "save as" it only saves one page of the 31 as BLANK. If I try doing normal save as, the saved file is un-annotated.

Please help... thanks

Recently, I am unable to open PDF's on Firefox. When I go to another browser and access the same site (such as a bank) I am able to view the PDF. I have tried some of the suggestions regarding extensions etc, but nothing seems to work. Is there a solution? Thanks, SVS

Firefox screws up showing .pdfs. The first view is fine but scrolling seems to overprint the first view without erasing it, if that makes sense, sorta like a double exposure. I can't get a screen cap either, which might just mean it's not a firefox issue at all, but I can view and screen cap .pdfs from any other application. I'm running Debian 12 up to date. When I need to view a .pdf I use Chromium, but I do prefer Firefox.

Dear Firefox Support Team,

I am encountering an issue where PDF files fail to display properly in Firefox, appearing as blank pages. This problem persists across multiple PDF documents, suggesting a potential browser compatibility or configuration issue.

Request: Please investigate this behavior to identify the root cause (e.g., rendering engine, plugin settings, or recent updates). Adjust Firefox’s default PDF handling settings or implement necessary fixes to ensure proper PDF display.

Additional Details:

• Firefox Version: All
• OS: Windows & Mac
• File link: https://res.mdpi.com/data/pharmaceuticals-18-00847-v4.pdf
• Steps to Reproduce: Open any PDF file → Blank page appears.

This issue impacts productivity and user experience. Kindly prioritize resolving it or provide workarounds. Thank you for your attention.

Best regards, Mia Yu [email removed]@mdpi.com/[email hidden]@qq.com

Hi, I have few laminating machines icons on my computer face but I can't open them there is a message saying I can't open this file,

I think I have a Firefox PDF reader on my computer.

Thank you Bob Robertson

Hi, would I be able to get a free PDF reader? I have few items on my computer face and I can not open a PDF say of one of my laminating machine. do Firefox or Mozell have a PDF reader I can download for free?

Bob Robertson