My site shows a blank white page

Why it happens

A blank page is almost always a PHP error that isn't shown on screen. The cause is the same as error 500: an incompatible extension, a PHP version change, or the server running out of memory.

Find the error

1. Look at the page source (Ctrl/Cmd + U). Empty source means a PHP error; full HTML with nothing visible points to a CSS or JavaScript problem.
2. Turn on error reporting: in Global Configuration, or in configuration.php set $error_reporting = 'maximum' and $debug = true.
3. Reload the page and read the message, or open your server's error log in the hosting panel.

Fix the usual causes

• An extension: disable the one named in the error (in the #__extensions table if the administrator is down).
• Memory: raise memory_limit to 256M.
• PHP version: check it matches what your Joomla and extensions support.

Good to know

• Remember to switch error reporting back to System Default afterwards: visitors shouldn't see error details.