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firefox failed to read configuration file

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  • 4 have this problem
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  • Last reply by cor-el

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Hi there!

Whenever I open Firefox, I receive a notification that suggests I reinstall the browser due to a configuration file error. However, I am still able to use the browser normally and my settings remain intact.

Is there anything I can do to address this notification without reinstalling Firefox? I would appreciate any guidance or suggestions you may have.

Thank you for your time, and I look forward to hearing back from you soon.

Best regards, sander

Hi there! Whenever I open Firefox, I receive a notification that suggests I reinstall the browser due to a configuration file error. However, I am still able to use the browser normally and my settings remain intact. Is there anything I can do to address this notification without reinstalling Firefox? I would appreciate any guidance or suggestions you may have. Thank you for your time, and I look forward to hearing back from you soon. Best regards, sander
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If you haven't solved this yet, this is a problem with an autoconfig.cfg file (name might be different) in the Firefox installation folder.

You can check what .js files are present in the "defaults\pref" folder in the Firefox program folder. The channel-prefs.js file that sets app.update.channel is a legitimate file in this folder, any other .js file is suspicious. You can open this suspect file in a plain text editor like Notepad (Mac: TextEdit) and please post its content to see whether that allows to identify what software created the file. Also please post the content of the autoconfig.cfg file referenced in this autoconfig.js file.

There shouldn't be a autoconfig.cfg file present unless you've created it yourself to initialize some prefs.

If you have this autoconfig.cfg file then best is to do a clean reinstall and delete the Firefox program folder to make sure that all files are removed before reinstalling a freshly downloaded copy of Firefox.

Possible content you might see in the autoconfig.js file in the "defaults\pref" folder.

// first line is a comment line
pref("general.config.filename", "autoconfig.cfg"); (this line specifies the autoconfig file)
pref("general.config.obscure_value", 0);