Firefox 3 Acrobat Reader Browser PDF Crash Bug Report

The Mozilla Forums have been talking about a weird Firefox 3 bug when trying to open an Adobe Acrobat PDF file within the browser window environment for some folks. I am one of those folks that is having a problem reading PDF files in Firefox. I feel like I’m hitting a brick wall on this one problem.


For some reason, when a pdf file is clicked on from the Web, Firefox 3 crashes and closes all windows abruptly and issues a crash report. This is also the case when trying to open a pdf file with the new Firefox 3 beta versions of the browser on my computer. However, the older Firefox 2.0 latest release runs fine and opens pdf files inside the browser window with no problems.

Some have said that this is no big deal, and just simply download the pdf files to your downloads folder, and then open it up with Acrobat Reader or some other PDF Reader program. I do have to say though, it is a big deal for me. I need to view PDF files regularly online, and I don’t want to clutter my downloads folder with pdf files that I don’t need. For example let’s take an online catalog that might have hundreds of individual parts sections, broken down by pdf file sections, that need to be quickly viewed to see which parts are the ones I am looking for online. If I have to download each section of the parts catalog before I know which one I really need, this can take much longer than simply clicking on the links and opening the pdf files in the browser window.

I have tried numerous things over the past month or two. I tried reloading Firefox 3, tried reloading Acrobat Reader 9, and tried disabling all the Firefox Add-ons with absolutely no success. I even tried going back to an older version of Acrobat Reader 8, but I still have the same exact problem with Firefox crashing and closing all the windows. In addition to all of those items, I also ran a registry cleaner program that fixes various problems with the computer software registries. None of this made any difference in the problem.

On top of this, I verified that PDF files will open in Google Chrome, Internet Explorer, Opera, SeaMonkey, and Safari web browsers all work with pdf files on the computer.

There is one way I can get Firefox to open a PDF file, and that is through the IE Tab add-on. The Firefox IE Tab add-on mimics Internet Explorer so a person can open pages within Firefox as though they are Internet Explorer pages. Actually, this add-on is extremely useful for websites that require Internet Explorer to view properly or to edit the pages for an IE only editor. So, when I click the PDF file and open it in a new IE tab, the file is opened properly using the latest version of Firefox.

I am using Windows XP Professional 32-bit operating system software with 4 GB of RAM and Service Pack 3 installed. along with all the latest Windows XP software updates. Note that the memory is only addressable to approximately 3.37 GB of the total 4 GB RAM because of the Windows 32-bit OS software limitations.  The processor is an AMD Phenom 9850 Quad-Core Processor operating at 2.50 GHz.

If anyone has any suggestions I’d appreciate it. Jim

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I had the same problem. Try to copy the nppdf32.dll from your Program Files/Adobe/Acrobat/Reader/Brwoser/ directory to Program Files/Mozilla Firefox/Plugins … (or use your similar path names). This did the job for me. PDFs open inside Firefox again like they should. No more crashes!

Regards, Bruno.

Jim Warholic

Tried copying the file. Doesn’t fix it.

The nppdf32.dll is the same version as that in the main Adobe Acrobat folder. That nppdf32.dll file gets updated when you reinstall Acrobat Reader.

There is something else in Firefox 3 and/or Acrobat Reader that are conflicting with one another.



I had this problem too. And like you, I did not consider it a small issue either. I had previously tried out Foxit Reader, but decided to change back to Adobe. Everything worked flawlessly again when I removed the easy recognizable foxit-plugin from Firefox’ plugin-folder. Maybe you have another conflicting pdf-viewer plugin lying around in your plugins folder too.

Jim Warholic

Hi Anonymous,

Your thoughts on the matter are greatly appreciated.

I started thinking it through again about your ideas with the plugin conflict. My first thought was no, that can’t be because I disabled all plugins to try it out, and still upon opening a PDF file, Firefox would close abruptly.

Then, I decided to look and see what other programs were installed, and I noticed I had two versions of Firefox 3 installed. So, I uninstalled the older of the two Firefox 3 programs thinking that was it. No luck; I still had the abrupt stop when opening a PDF file.

I started looking a little closer at the installed PDF addons that I did have. I noticed the PDF Download by Nitro PDF Software installed as an Addon. On the default action, I had selected show Pop Up. I switched it to open PDF file in a new tab. And guess what, it worked. Then I uninstalled PDF Download, and I was back to the same problem of Firefox shutting down again. So, I reinstalled PDF Download and am running it with open PDF in another tab, and everything seems to be working when I open a PDF file.

So, it is working better than it was, but Firefox still has a problem when I select the other popup option selection form of what to do with a PDF download. Maybe there still is a conflict with something else.

Maybe someone else has more insight into this problem. If so, leave your comments here.

Best regards,



It definitely has something to do with the other plug ins. I just disabled them all and now my pdfs open in Firefox 3. Not sure if it was AdBlock, Video Downloader, or one of the others I had.


i am suffering from the same problem, and similarly discovered the strange fix: ctrl+click. or, more precisely, open link in new tab. if i do that on a PDF link, it loads fine. if i try to open it in the current window: crash-a-roo.



Yeah, it’s the addons. I had some embedded object add-ons installed. I got rid of them and the crashes were gone.

Jim Warholic

Yep, I think you are right.

My problem was still happening even after I disabled all the addons. However, when I created a new profile, and started up Firefox using the new profile, the problem went away. So, what I have been doing, is rebuilding the new profile with only the addons that I really need.

Rebuilding a profile requires some work however. Getting my bookmarks over was no problem, but getting all my saved passwords was slightly more problematic. I used an addon that exports the passwords, and then the same addon in the new profile to import the passwords.

I’m sure there are other ways around this, but it worked for me.

I still don’t have the new profile configured exactly the way I want, but I am getting there. As I add an addon on (tongue twister) I recheck to see if pdf documents still open in Firefox without crashing it. I recently purchased the new Adobe Acrobat 9 Pro Extended version for PDF files. So, now I have much more flexibility on creating PDF files.


I found that ‘Download Embedded 0.5’ caused this issue to rear its ugly head.

Thanks for the posts!!

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