Hey FireFoxFan1, really sorry to see this kind of bug can occur. Philipp, a community member may have found an answer. We have both tested your link and: - we can access your main pdf with 18 pages. Try to access this document from another computer and/or another network the document is pretty big. - for your second problem, it appears IDs are different and you should get 2 different documents. We can also reproduce your issue and this is the pdf viewer in Firefox is not really dedicated to present sophisticated documents like these ones. Unfortunately, you cannot see these documents in your browser, you have to download and open them in a pdf reader such as Acrobat Reader. Can you confirm you see both documents in a pdf reader ?

- I've been able to view PDFs larger than this one. It's not the size that's giving me problems, I don't think.

- I've never had a problem reading these in my Acrobat Reader on my computer. I'm really confused as to why the second file loads as the first one.

Honestly, none of these three documents I posted about are unusual. I can open up plenty of different PDF files in the browser, many hundreds of pages and with pictures. There is nothing about these that's particularly complicated or special, so I'm honestly confused by the explanation.

They work for me in the current Firefox release (56).

Web Console:

• http://lansingmi.gov/DocumentCenter/View/3775

PDF 1418d5db3b4b2648bf01152cd71a69bf [1.5 Adobe PDF library 15.00 / Adobe Illustrator CC 2015 (Windows)] (PDF.js: 1.8.618)

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History -> Show All History" or "View -> Sidebar -> History").

Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks and history and cookies and passwords and cache and exceptions, so be cautious. If you have a password or other data from that domain that you do not want to lose then make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of involved files.

If you revisit a 'forgotten' website then data from that website will be saved once again.

• https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox

You can create a new profile to test if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

To be clear, I'm having to very different issues, which is why I seperated them in my post. The first issue is of the Denver 18-page file simply not loading. The second issue is of two different files that will load, but loading as the same file.

I'll try some of these to see if this works. My current settings don't save passwords. It's always been set to custom settings for history, and specifically "accept cookies from websites" and "clear history when firefox closes," which is why I'm confused about why the second issue is going on. In the "Settings for Clearing History" the only boxes not checked are the "Data" boxes (i.e. Site preferences and Offline website data.).

BTW, I'm already on Default theme.

By default, Firefox will use its built-in PDF Viewer. Maybe you should try another viewer using these steps:

1. Click the hamburger menu button Menu (the one with 3 sticks) and choose Preferences.
2. Select the Applications panel.
3. Find Portable Document Format (PDF) in the list and click on it to select it.
4. Click on the drop-down arrow in the Action column for the above entry and select the PDF viewer you wish to use.
5. Élément de liste numérotée Close the about:preferences page. Any changes you've made will automatically be saved.

From the documentation page: How to disable the built-in PDF viewer and use another viewer.

First, the "hamburger" menue does not show an option for "preferences" in my Firefox browser. Secondly, even in that case, what other PDF viewer would I use? Is there another one that can be used within the browser? Or would it open seperately like in my Acrobat Reader? I'd always enjoyed the simplicity of the in-browser viewer, particularly when they were using Abode's viewer.

Firefox seems to have a problem with the PDF files on the lansingmi.gov website. I don't know if there are some layers in the file that Firefox can't handle. There are different files downloaded as saving both pages and opening in an external viewer shows.

Thanks. So at least that particular problem seems to be on their end. BTW, can you explain smorele's comment to me? I can't find what he's telling me to look for in this newest version of Firefox.

Thank you so much cor-el for helping us :) FireFoxFan1, I attach a screen from my main menu, hope this will help you understanding may say.

Thanks. I'll switch it to by Adobe Acrobat reader, but I'm not pleased about having to go outside the browser for something that was once a successful in-browser plugin...or rather, at least I thought it was successful. I know Flash was a big problem for Firefox and affected a lot of the functioning of the browser, but I thought the embedded Adobe Acrobat functioned pretty well with the browser.

At the moment, this is the only solution we can propose, hoping core pdf viewer will be improved in next firefox versions.