You have probably forgotten to create and edit your .htaccess file. If .htaccess file does not exists, you may create it by renaming the htaccess.txt file included in Joomla! root directory. Then make sure that the RewriteCond and RewriteRule directives are uncommented in the section for 3rd party SEF modules (almost end of the .htaccess file). Finally set the RewriteBase to match the root URL of your Joomla! installation at the server (this means the path to root with out the server name - e.g. if your Joomla! is installed as http://www.domain.org/somedir/myjoomlaroot, that the right setting would be RewriteBase /somedir/myjoomlaroot). Please see component documentation for more details.

There is probably some misspelling or invalid configuration in your .htaccess file. Please recheck it and do needed modifications. Please see documentation for details.

Since the JoomSEF version 1.3.3, there is an update utility provided. You can upgrade your installation easily by clicking "Update" button and the newest version will be downloaded and upgraded automatically for you. The automatic upgrade will preserve your current configuration and all generated URLs.

As alternative or for older versions, you can use the default Joomla!'s component unistall and install utility to remove the old version and install the new. However if you do so, your configuration and manually entered URLs (if you have any) will be lost and you will need to set them again. Therefore you are strongly adviced to backup them using provided utility first. Also you can do the update manually by replacing the files from the distribution package. This is however recommended to experienced users only.

If you are facing duplicate content items links e.g. http://yoursite.you/article.html, http://yoursite.you/article-2.html, etc. that lead to the same content, this is most probably caused by so called "Itemid" variable (although there may be other reasons also).

The Itemid is internal Joomla! variable used to identify the source of a URL link. E.g. main menu or sub menu item that your visitor used to get to a certain content. According to this variable, different Joomla! configurations are applied - e.g. what template will be used or what modules will be visible, etc.

Since JoomSEF 1.4.0, several new configuration options are provided in "Advanced configuration" section. The option "Exclude source info" may be used to exclude the Itemid variable from the URL and thus eliminate the duplicates caused by it. However, ignoring it completely may lead to unwanted Joomla! functionality, like not swithing the templates as desired or so. Whether this will be a problem for you or not depends mainly on the way how your site is designed and how complicated it is. If you need to fix this, the Itemid should be "reappended" to the SEF URL as an extra part using the option "Reappend source". Then the resulting URL will look like http://yoursite.you/article.html&Itemid=xy.

The JoomSEF component always tries to generate search engine friendly URLs. In many cases, and for standard simple components, this behaviour is sufficient. However, for some more complex components with special funcitonality this may not be efficient enough or may even cause the components to stop working. In such case, you may choose to disable SEF generation for such module in JoomSEF configuration. If you would still like to have SEF URLs for such components, a special extension defining rules for how the specific components's URLs should be treated needs to be written. This extension might be either developed by the module author or we can include it in our distibution. At presence, we have done support for DocMan and Joomlaboard components. Please contact us if you want certain module to be also supported.

If you have updated from previous major version, e.g. from 1.4.0 to 1.5.0, you may experience that some of the URLs are duplicated, even though they were okay previously. This may be caused because the format of SEF URLs stored in your database has changed and the new URLs are lokking slighly different than the old ones. In such case, if you do not want JoomSEF to regenerate them automatically (by either purging the existing one or deleting them manually) or if you have many customized URLs, you will need to use the JoomSEF DB upgrade script 1.5.0 to update the DB for you. Your are highly encouraged to backup your DB prior to doing this! After updating, the old URLs will have the same format as the new ones, so they will be matched correctly and no duplicates will appear.