If you try to modify Firefox’s settings using about:config, you have probably seen the message, “This might void your warranty!”. This warning tells you that you should not configure or edit any settings using about:config if you don’t understand what you are doing because it could affect the performance, stability and security of Firefox.

Firefox's warning message about voiding the warranty

You may have disabled this message by unchecking the Show this warning next time check box so you wouldn’t have to click the I’ll be careful, I promise! button every time you want to change a setting. What if you want to turn the message back on? There is a setting in about:config that controls this message and allows you to easily re-enable the message.

To do this, enter about:config in the address bar and press Enter.

Entering about:config in address bar

In the Filter edit box, enter general.warnOnAboutConfig. The results display automatically as you type the text. Double-click the text in the Value column to change it to true.

Filtering for general.warnOnAboutConfig setting

NOTE: When the value is false, you will notice that the setting displays in bold. When a setting displays in bold, it means that setting has been changed from its default value.

04_warn_on_about_config_setting_false

After changing the general.warnOnAboutConfig setting back to true, the warning message will display each time you access about:config.

by Lori Kaufman