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Why Am I again having downloads abort after another firefox update


The error message is an unknown error has occurred please try again. The files are often left as bit parts depending on what download service they are from. I should not have to disable real time scanning because of this problem. Real Time scanning is one of the necessities of anti virus protection and downloads using firefox should work with my anti virus real time protection and not abort. I reverted back to the download box which got replaced in an upgrade of firefox a few months back because of this problem and it is now prevalent again.

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Installed Plug-ins

  • Shockwave Flash 11.8 r800
  • Adobe PDF Plug-In For Firefox and Netscape 11.0.04
  • SiteAdvisor
  • McAfee MSC FF plugin DLL
  • VLC media player Web Plugin 2.0.6
  • Google Update
  • Adobe Shockwave for Director Netscape plug-in, version
  • Next Generation Java Plug-in 10.25.2 for Mozilla browsers
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • 5.1.20513.0
  • McAfee Virtual Technician plugin
  • Windows Presentation Foundation (WPF) plug-in for Mozilla browsers
  • DRM Netscape Network Object
  • Npdsplay dll
  • DRM Store Netscape Plugin


  • User Agent: Mozilla/5.0 (Windows NT 5.1; rv:24.0) Gecko/20100101 Firefox/24.0

More Information

Ed 95 solutions 596 answers


I'm also using Firefox v24 with the new download UI and real time scanning and am not having this issue.

As a first step I suggest you try the suggestions in the following article:

What to do if you can't download or save files

Do any of these work?

If not please try booting Firefox into Safe Mode and testing again. Does the problem still occur in Safe Mode?

Troubleshoot Firefox issues using Safe Mode

If the problem does not occur in safe mode then most likely one of your add-ons or a setting is causing the problem. Follow the instructions in the article above to troubleshoot and identify the culprit.

If the problem still occurs in safe mode then I suggest doing a Firefox Reset. This will return Firefox to its default settings. Your personal data (bookmarks etc) will be saved but you will need to reinstall your add-ons.

Reset Firefox – easily fix most problems

I hope this helps. Let me know if not.

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Helpful Reply

It usually depends on whether your security software waits for Firefox to finish the download and pass control to have your anti-virus scan the file or that your anti-virus software already starts scanning while Firefox is still downloading. Firefox closes the file after saving each chunk and that can make your AV software think that the download has already finished.

Question owner

Thank you Cor-el ! This is what is happening but it has only started happening again since the upgrade to Firefox 24. I am downloading with the Mcafee real time scanner turned off at the moment to see if the downloads complete. I will post if I am successful. The problem is intermittent when the Real-Time scanner is on as I did manage to download a file last night with it on. A Mcafee update downloaded earlier and about 5-10 minutes after my downloads aborted with the message the Source file could not be read. Is there anything that can be done to rectify this problem? Is it Mcafee or Firefox?

Question owner

I can confirm that this problem is intermittent. The files abort at the very last few seconds of the download sometimes, a bit part is left over or there is nothing. When I turn off McAfee real time scanner the files complete. This has only been happening since the Firefox 24 upgrade but I have had this problem before after other Firefox upgrades. The error message is an unexpected error occurred.

What can be done to fix this problem?

Modified by Theperson