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When I download files in Firefox they only get about 99% complete even though it tells me they downloaded successfully.


9 out of 10 times my download gets truncated in Firefox. For example, let's say I was downloading a 42.2 mB file, it would get to about 42.18 and then complete. I would then try to open the file to find it was corrupt. I would then open up IE9 and download the exact same file, and I would get the full 42.2 mB and the file would open flawlessly. I have tried disabling all extensions/addons, nothing. I have reinstalled Firefox cleanly a few times, no dice. I have tried disabling any file system protections I have, nada. I'm at a loss right now as to what else I can try. I love Firefox, I've been using it since it's original release, but I need to be able to download. Every other browser I've tried works great in that department, except for Firefox all of a sudden. Anyone have an idea?

Additional System Details

Installed Plug-ins

  • Google Update
  • Shockwave Flash 11.5 r502
  • Next Generation Java Plug-in 10.11.2 for Mozilla browsers
  • NVIDIA 3D Vision plugin for Mozilla browsers
  • NVIDIA 3D Vision Streaming plugin for Mozilla browsers
  • Adobe PDF Plug-In For Firefox and Netscape 11.0.01
  • VLC media player Web Plugin 2.0.2
  • iTunes Detector Plug-in
  • Adobe Shockwave for Director Netscape plug-in, version
  • Plug-in for detecting Nero Kwik Media.
  • 5.1.10411.0
  • Intel web components updater - Installs and updates the Intel web components
  • Intel web components for Intel® Identity Protection Technology


  • User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/20100101 Firefox/18.0

More Information

Tyler Downer
  • Administrator
  • Moderator
1164 solutions 6629 answers

The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

  1. Go to Firefox > Help > Troubleshooting Information.
  2. Click the "Reset Firefox" button.
  3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
  4. Firefox will open with all factory defaults applied.

Further information can be found in the Reset Firefox – easily fix most problems article.

Did this fix your problems? Please report back to us!

Helpful Reply

Just tried that, but the issue persists. Any other ideas?

Question owner

Does anyone have any idea what could be the cause?

  • Top 10 Contributor
  • Moderator
10738 solutions 96600 answers

It is possible that anti-virus software is corrupting downloaded files or is otherwise interfering with downloading files.
Try to disable the real-time (live) scanning of files in your anti-virus software temporarily to see if that makes downloading work.


Question owner

I have tried disabling all filesystem protections I have, didn't work. Also tried everything listed in that article already, still the same problem.