Editing module shows module XML data not available

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Some modules installed in Joomla 3.4 and higher (that worked in Joomla 3.3.6) show an error when attempting to edit.

Errors Reported[edit]

Module XML data not available when going to edit module (with no fields appearing).

Versions Affected[edit]

Info non-talk.png
General Information

This pertains only to Joomla! version(s):- 3.4 and higher

What is the Cause?[edit]

Modules that have capital letters in their elements are now forced to lowercase during module installs (as a result of some standardisation in the installer). This results in case-sensitive systems with the XML file being unable to be found.

How to Fix[edit]

Ensure the module element

<filename module="mod_articles_category">mod_articles_category.php</filename>

has no capital letters (as well as the appropriate XML file).