"404 Page not found" error after clicking any link

Homepage is working and SEF URLs are generated, but when clicking any link, "404 - Page not found" is generated.

1. Make sure that .htaccess file exists

Make sure that .htaccess file exists in the Joomla! site root. If .htaccess file does not exists, you may create it by renaming the htaccess.txt file included in Joomla! root directory.

Also make sure that the .htaccess file is processed by the server. Some servers may ignore the file. You can test it by adding some incorrect line to the file. If you do so and try to access the site, it should return 500 Internal Server Error. In such case, the .htaccess file is processed. If nothing happens, then it is most likely ignored and you need to contact your server admin to ask him to allow .htaccess usage or to put the neccessary directives in global server configuration file.

2. Check the rewrite rules .htaccess file

Make sure that the RewriteCond and RewriteRule directives are uncommented in the section for 3rd party SEF modules (almost end of the .htaccess file) - this only applies to Joomla 1.0.x and JoomSEF 2.x. In Joomla 1.5.x there is only one set of rules that is already uncommented by default.

3. Check RewriteBase value and adjust it if needed

Finally, make sure to set the RewriteBase value to match the root URL of your Joomla! installation at the server.

This means the path to root without 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). If your site is located in domain root, the RewriteBase may either stay commented our or have / value. However, even if in root some servers require uncommenting it and setting explicit value (then set it simply to RewriteRule /).

4. When using JoomFish, make sure JfRouter is DISABLED

If you use JoomFish and JoomSEF at the same time, there may be a conflict between their routers. As JoomSEF router does all that JoomFish router, you can disable the JfRouter to solve this problem.

For more details, see also JoomSEF documentation.