Adwcleaner reports prefs.js in Firefox and file keeps recreating itself.

Hello, this is my first post/topic in here, please let me know if I've done something incorrectly.

I use Firefox, and recently when I did a scan with AdwCleaner v6.030 it showed me my prefs.js file located here:

C:\Users\UserNames\AppData\Roaming\Mozilla\Firefox\Profiles\5z7fppjh.default-1478561597170\prefs.js

This file, even when I do a clean with Adwcleaner or remove it manually by deleting it myself keeps showing up, probably the next time I close and start firefox. I've even refreshed firefox, uninstalled and reinstalled, but the file still keeps being remade. Could it be a false positive? I've always trusted Adwcleaner and hadn't had problems with it before.

I get the suspicion that it might be made by one of the addons I have and the prefs.js file could be practically harmless, but of course if it's really a virus I'd like to know what else I can do to remove it permanently since it keeps being recreated. I think last time I deleted it manually it deleted my firefox appearance and minor settings like the positions of the firefox buttons I have re positioned with Firefox's customize tool (another reason it makes me think it could be a false positive) and stuff like that. Any ideas? I have the latest firefox version (49.0.2). The addons I currently have are Blur, UBlock Origin, x-kit and NoScript. I haven't touched the Plugins since reinstalling firefox and they are OpenH264, Primetime Content Decryption Module, Shockwave Flash, Widevine Content Decryption Module, and Silverlight Plug-in. Should any of those be set to 'never activate' for extra security? Anything else I should have for extra security? I do also do regular scans with Malware bytes (free version) and MCE. 

Thank you for your help.

Edited by katerinafm, 10 November 2016 - 07:17 PM.

You can ask the developers (fr33tux or cocochepeau) a question, report a problem or make suggestions at the official Malwarebytes AdwCleaner Forum...include the log file.

Our staff does not know the detailed inner workings of the program and we would have to contact and refer the developers to this topic. Your best option would be to ask yourself and wait for a reply.

Okay thank you I'll remember that for next time. I appear to have found the cause and it's nothing malevolent.

 

Unfortunately, I am not permitted anybody to help in this forum, but

prefs.js is perfectly normal Firefox user settings and options file and it should be there. 

It contains the Firefox user settings and preferences.

 

I imagine that is usually the case. After a tiny bit of testing it appears to be a line of code that appears when I install the x-kit addon. Didn't use to do that in the past which is weird, but it explains it since it's not an official addon anymore. The line of code in the log file appears harmless:

Firefox pref Found:  [C:\Users\Users\AppData\Roaming\Mozilla\Firefox\Profiles\5z7fppjh.default-1478561597170\prefs.js] - "extensions.xkit7.extension_xkit_preferences" -  "{\"script\":\"//* TITLE XKit Preferences **//\\n

I notified them of the possible false positive and if a new problem appears I'll go to the malwarebytes forums. I've just never had a problem with that addon before or a file that adwcleaner couldn't clean for good so I wanted to be more sure.

XKit is an extension for Firefox and Chrome, which is not mandatory. If you do not like it, then do not use it. You have installed it yourself, if it is there.

Homepage: http://www.xkit.info/seven/download/

 

XKit is an extension for Firefox and Chrome, which is not mandatory. If you do not like it, then do not use it. You have installed it yourself, if it is there.

Homepage: http://www.xkit.info/seven/download/

I know I installed it myself. Like I said, I figured out the problem and it appears it's all good.