Windows 10 bereikte EO (einde ondersteuning) op 14 oktober 2025. Als je Windows 10 gebruikt, lees dan dit artikel.

Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

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Help I need help. i get this message'Firefox could not install this item because "install.rdf" (provided by the item) is not well-formed or does not exist. Please contact the author about this problem.' How do i fix this?

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  • Laatste antwoord van cor-el

Firefox could not install this item because "install.rdf" (provided by the item) is not well-formed or does not exist. Please contact the author about this problem.

Well that is the message i get. I can still use firefox(version3.6.8)

Firefox could not install this item because "install.rdf" (provided by the item) is not well-formed or does not exist. Please contact the author about this problem. Well that is the message i get. I can still use firefox(version3.6.8)

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That is a problem with installing an add-on. You can try removing some files related to add-ons.

  1. Open your profile folder in Windows Explorer, for details of how to find it see profiles.
  2. Close Firefox
  3. In the profile folder delete extensions.rdf, extensions.cache and extensions.ini
  4. Open the extensions folder that is inside the profile folder
  5. If there is a folder called staged-xpis delete it.
  6. Restart Firefox to see if the error has gone

You get that error if an extension is using an old and no longer supported method to install a plugin.

Which plugin are you trying to install?

See also http://kb.mozillazine.org/Unable_to_install_themes_or_extensions