By website you mean www.mozilla.org or www.mozilla.org/firefox/all/

Firefox versions for Windows, Mac OSX, and Linux on mozilla.org are not infected and if they were it would have been dealt with quickly by Mozilla and also been a hot topic around.

How do you figure they are infected?. Some antivirus clients still have a issue with the small Firefox stub installer (even though it has existed since Fx 18) in claiming some form of malware yet has no problem with the full setups on Windows.

Or just because you see something suspicious in Firefox on Windows after a Firefox install from Mozilla does not mean it came with Firefox. It could be some malware already on your PC that is targeting Firefox specifically or because it is default browser.

You could at least say what malware your unnamed scanner found and where?

Since you did not say for what OS and Locale of Firefox I uploaded the Win64 Firefox 45.0.1 to virustotal and it was clean as expected. Detection ratio: 0 / 56 https://www.virustotal.com/en/file/5aed341f8d30cbe676f68fc8f29a5e74059b2df52da9786e8f7576ae50444ef3/analysis/1459758088/

Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of.

You can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• Anti-Rootkit Utility - TDSSKiller
• AdwCleaner (for more info, see this alternate AdwCleaner download page)
• Hitman Pro
• ESET Online Scanner

Microsoft Security Essentials is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one. Windows 8 has antivirus built-in already.

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Is this message coming from your security software?

Note that some security software erroneously reports the small Firefox stub installer as being infected. In such a case you can download the full Firefox version.

Try this:

• Download the Firefox installer and save the file to the desktop
  *https://www.mozilla.org/en-US/firefox/all/
• Start the installation with a double-click on the desktop icon

Hi, I was getting Generous Deals and Smart search trojans on the computer and Malwarebytes identified the source as Firefox. I shredded the download files and all the associated files for Firefox and downloaded from Mozilla, ran several virus and malware sweeps restated several times to make sure all was up to date downloaded from Mozilla again and was back where I started. I have an ASUS K31BF running Windows 10 Version 10.0.10586 Build 10586 the computer is new and was scanned with McAfee before anything was downloaded

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

The malware will almost certainly be hiding on your computer so I suggest you try scanning with all tools mentioned in the posts above before attempting another reinstall of Firefox.

• Especially note the results from using adwcleaner: http://www.bleepingcomputer.com/download/adwcleaner/

Additionally make a check of all shortcuts Firefox uses for instance the desktop Firefox icon. Right click and check its properties, in case any odd web address is tagged on to the end after firefox.exe

Also please say what Firefox language version it is is it the default en-US ? You may yourself want to try submitting that to virus total https://www.virustotal.com . Also scan the downloaded file with Malwarebytes and MacAfee to confirm prior to install that they show it is clean.