What goes wrong and how to fix it.
BLANK PAGE OR 500 ERROR
Enable error reporting in configuration.php temporarily, or read the cPanel error log.
Usually an extension conflict or a PHP version incompatibility.
Rename the template or disable extensions by editing the database if you cannot reach the administrator area.
CANNOT LOG IN TO ADMINISTRATOR
Create a new super user account directly in the database, or use the cPanel-based reset if your installation supports it.
Check the session and cookie settings in configuration.php if login appears to succeed and returns you to the login page.
404 ON EVERY PAGE BUT THE HOME PAGE
Search engine friendly URLs are enabled but the htaccess file was not renamed from its supplied name. Rename it.
IMAGES OR LAYOUT BROKEN AFTER MIGRATION
The site URL in configuration.php still points at the old location. Edit the live site and log path values, which contain absolute paths.
This is the most common Joomla migration problem.
EXTENSION UPDATE FAILS
Check file permissions and that the temporary directory path in configuration.php is correct.
AFTER A PHP VERSION CHANGE
Older Joomla versions break on newer PHP. Check compatibility before changing.
