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Failed to read the configuration file.Please contact your system administrator.

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Unable to open Firefox and Getting error below when trying to open the Firefox after hard coding the proxy settings for Firefox browser on Windows 10.

Failed to read the configuration file.Please contact your system administrator.

Unable to open Firefox and Getting error below when trying to open the Firefox after hard coding the proxy settings for Firefox browser on Windows 10. Failed to read the configuration file.Please contact your system administrator.

All Replies (4)

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Problem description: Upon launch of FF, message is displayed and FF fails to launch

Solution: Wiped out Firefox and installed from scratch. Resolved message/problem.

Problem returned: Had to end Firefox process instead of closing properly. Message/problem returned.

Solution: Removed some files in FF installation directory (instead of stupid reinstall) and resolved.

Problem returned again!!!

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Did you create a mozilla.cfg file in the Firefox program folder to initialize prefs.?

You get this error when you specific using mozilla.cfg, but Firefox finds that there is a problem with the file or the file is missing. Make sure that mozilla.cfg doesn't have a hidden .txt file extension appended (mozilla.cfg.txt).

See also Configuration:


Can you please post the content of mozilla.cfg if the above didn't help?

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Below are the content of .cfg and .js files.

Mozilla.cfg file: // lockPref("network.proxy.type", 5);

local-settings.js pref("general.config.obscure_value", 0); pref("general.config.filename", "mozilla.cfg");

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If the name all lowercase: mozilla.cfg and is the file located in the main profile folder and not in the same location as local-settings.js?

  • (64-bit Firefox) "C:\Program Files\Mozilla Firefox\"
  • (32-bit Firefox) "C:\Program Files (x86)\Mozilla Firefox\"

Note that best is to start local-settings.js as well with a comment line (//).

You can check the Browser Console immediately after starting Firefox for error messages.