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Èròjà atẹ̀lélànà yii ni a ti fi pamọ́ fọ́jọ́ pípẹ́. Jọ̀wọ́ béèrè ìbéèrè titun bí o bá nílò ìrànwọ́.

Why would user.js keep getting created on PC boot-up?

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My user.js file simply will not die. Every morning I start my computer to have the about:config setting 'general.useragent.override' and a user.js file which contains:

user_pref("general.useragent.override", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0.1) Gecko/20100101 Firefox/4.0.0; xs-16Qc283ciRs;CiSxfh;");

So every morning I delete and/or edit user.js and reset 'general.useragent.override' in about:config, if I don't I'm constantly badgered about having an out-of-date browser by everyone including Mozilla. Even this posting miss identified my Firefox version because I hadn't yet cleared out this setting.

I have determined that user.js is definitely being created/overwritten on start-up but I can't tell what's doing it.

My user.js file simply will not die. Every morning I start my computer to have the about:config setting 'general.useragent.override' and a user.js file which contains: user_pref("general.useragent.override", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0.1) Gecko/20100101 Firefox/4.0.0; xs-16Qc283ciRs;CiSxfh;"); So every morning I delete and/or edit user.js and reset 'general.useragent.override' in about:config, if I don't I'm constantly badgered about having an out-of-date browser by everyone including Mozilla. Even this posting miss identified my Firefox version because I hadn't yet cleared out this setting. I have determined that user.js is definitely being created/overwritten on start-up but I can't tell what's doing it.

Ti ṣàtúnṣe nípa boredtotears

Ọ̀nà àbáyọ tí a yàn

"Something" got installed on that PC in the past that is reinstalling that user.js file, probably when your PC is turned on and Windows is booted up.

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0.1) Gecko/20100101 Firefox/4.0.0; xs-16Qc283ciRs;CiSxfh;

Reading what is incorrect with that User Agent string; rv:2.0.1 = Gecko version of Firefox 2.0 from like 2006 - 2009 4.0.0 = from 2011 and either of those "tell" websites that you are using an old version xs-16Qc283ciRs;CiSxfh; = probably used to track users who inadvertently installed that Malware


You need to locate and remove whatever installed that garbage. View the Windows Control Panel > Add / Remove Programs to see what got installed that you don't need or don't use. Then uninstall the likely culprits.

Or do a search of the Windows Registry for that xs-16Qc283ciRs;CiSxfh; If you find it, remove it from the Registry.

Another solution would be to lock the 'user.js file after removing that line of code. With an empty & locked user.js file it can't be edited or reinstalled. IMO, that might be the most expedient and/or best solution for your problem.

Reinstalling Firefox or creating a new Profile won't do anything as ling as that crap is still hiding in Windows and the Registry. So don't even think of doing that; waste of time, IMO.

Ka ìdáhùn ni ìṣètò kíkà 👍 0

All Replies (2)

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Ọ̀nà àbáyọ Tí a Yàn

"Something" got installed on that PC in the past that is reinstalling that user.js file, probably when your PC is turned on and Windows is booted up.

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0.1) Gecko/20100101 Firefox/4.0.0; xs-16Qc283ciRs;CiSxfh;

Reading what is incorrect with that User Agent string; rv:2.0.1 = Gecko version of Firefox 2.0 from like 2006 - 2009 4.0.0 = from 2011 and either of those "tell" websites that you are using an old version xs-16Qc283ciRs;CiSxfh; = probably used to track users who inadvertently installed that Malware


You need to locate and remove whatever installed that garbage. View the Windows Control Panel > Add / Remove Programs to see what got installed that you don't need or don't use. Then uninstall the likely culprits.

Or do a search of the Windows Registry for that xs-16Qc283ciRs;CiSxfh; If you find it, remove it from the Registry.

Another solution would be to lock the 'user.js file after removing that line of code. With an empty & locked user.js file it can't be edited or reinstalled. IMO, that might be the most expedient and/or best solution for your problem.

Reinstalling Firefox or creating a new Profile won't do anything as ling as that crap is still hiding in Windows and the Registry. So don't even think of doing that; waste of time, IMO.

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In addition to the built-in msconfig, Microsoft offers another tool for discovering (and turning off) what runs at startup:

Autoruns for Windows