View source for Editing module shows module XML data not available

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<noinclude>{{Joomla version|version=3.4.0}}</noinclude>
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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.
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== Errors Reported == <!--T:2-->
''Module XML data not available'' when going to edit module (with no fields appearing).
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== Versions Affected == <!--T:7-->
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{{TTWP|refers_to|<translate><!--T:3-->
3.4 and higher</translate>}}

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== What is the Cause? == <!--T:4-->
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.
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== How to Fix == <!--T:5-->
Ensure the module element
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<source lang="php">
<filename module="mod_articles_category">mod_articles_category.php</filename>
</source>

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has no capital letters (as well as the appropriate XML file).</translate>

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[[Category:Version 3.4.0 FAQ]]
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