If that is part of the Firefox application, you would need to reinstall Firefox. It is not in the profile.

well, I couldn't found the "update.rdf" file by my computer (just only found the "install.rdf" file. damn't - F.F14 version) by the way, thank you

I wonder whether it is only retained until the update is completed? Perhaps if you load an old version of Firefox and request an update you can get a copy of the file that way?

Do you mean an update file to update Firefox or an update file for a specific extension? The Firefox update uses an XML file for update, so it is more likely that you are referring to an extension. *https://aus3.mozilla.org/update/3/%PRODUCT%/%VERSION%/%BUILD_ID%/%BUILD_TARGET%/%LOCALE%/%CHANNEL%/%OS_VERSION%/%DISTRIBUTION%/%DISTRIBUTION_VERSION%/update.xml *[https://versioncheck.addons.mozilla.org/update/VersionCheck.php?reqVersion=2&id={8A6C82A1%2DF6C9-481a-AAE7-C96444C9A754}&version=6.1.0.1&maxAppVersion=99.*&status=userEnabled&appID={ec8030f7%2Dc20a-464f-9b0e-13a3a9e97384}&appVersion=15.0&appOS=WINNT&appABI=x86-msvc&locale=en-US&currentAppVersion=15.0&updateType=97&compatMode=normal]

Thank you . solved the my problem