A white screen in WordPress

So you activated/updated a plugin, changed a setting or maybe did some custom coding and now all you see is a white screen om your WordPress website? This annoying white screen, also known as the ‘White Screen Of Death’, is the result of a suppressed PHP error. The PHP error can be caused by many different things and as long as you’re only seeing a white screen, you’re not likely to find out what.

What is causing the error

You most likely have a suspicion of what is causing the error. If you’ve got the WSOD right after updating a plugin, it’s most likely caused by that plugin. The actual cause of the error can be caused by a variety of different things and the recently updated plugin might not even be the one to blame. The best thing you can do at this point is to seek for support from the plugin author(s) but before you do so let’s get a ‘stack trace’ of the error.

A stack trace allows tracking the sequence of nested functions called – up to the point where the stack trace is generated

Simply put, the stack trace doesn’t only display the error but also the ‘execution path’ of the code. This is extremely helpful for the developer(s) of the plugin and they will be able to help you a lot better when you provide them a stack trace.

Displaying the stack trace

Displaying a stack trace is pretty simple. Juliette wrote a great code snippet that you can use to enable the output of the stack trace on your website. Copy the snippet below and paste it in your wp-config.php. Be sure to replace the define('WP_DEBUG', true); with the line that currently contains WP_DEBUG and paste the rest of the code below it.

define('WP_DEBUG', true); if ( WP_DEBUG ) { /** * Turn on error logging and show errors on-screen if in debugging mode */ @error_reporting( E_ALL ); @ini_set( 'log_errors', true ); @ini_set( 'log_errors_max_len', '0' ); /** * Change the path to one on your webserver, the directory does not have to be in the web root * Don't forget to CHMOD this dir+file and add an .htaccess file denying access to all * For an example .htaccess file, see https://gist.github.com/jrfnl/5953256 */ //@ini_set( 'error_log', '/path/to/writable/file/logs/error.log' ); // Ini sets @ini_set( 'display_errors', true ); // Show errors on screen @ini_set( 'html_errors', true ); @ini_set( 'docref_root', 'http://php.net/manual/' ); @ini_set( 'docref_ext', '.php' ); @ini_set( 'error_prepend_string', '<span style="color: #ff0000; background-color: transparent;">' ); @ini_set( 'error_append_string', '</span>' ); if ( ! defined( 'SAVEQUERIES' ) ) { define( 'SAVEQUERIES', true ); } if ( ! defined( 'WP_CACHE' ) ) { define( 'WP_CACHE', false ); } if ( ! defined( 'SCRIPT_DEBUG' ) ) { define( 'SCRIPT_DEBUG', true ); } if ( ! defined( 'WP_DEBUG_LOG' ) ) { define( 'WP_DEBUG_LOG', true ); } if ( ! defined( 'WP_DEBUG_DISPLAY' ) ) { define( 'WP_DEBUG_DISPLAY', true ); } /** * Adds a backtrace to PHP errors * * Copied from: https://gist.github.com/625769 * Forked from: http://stackoverflow.com/questions/1159216/how-can-i-get-php-to-produce-a-backtrace-upon-errors/1159235#1159235 * Adjusted by jrfnl */ function process_error_backtrace( $errno, $errstr, $errfile, $errline ) { if ( ! ( error_reporting() & $errno ) ) { return; } switch ( $errno ) { case E_WARNING : case E_USER_WARNING : case E_STRICT : case E_NOTICE : case ( defined( 'E_DEPRECATED' ) ? E_DEPRECATED : 8192 ) : case E_USER_NOTICE : $type = 'warning'; $fatal = false; break; default : $type = 'fatal error'; $fatal = true; break; } $trace = debug_backtrace(); array_shift( $trace ); if ( php_sapi_name() == 'cli' && ini_get( 'display_errors' ) ) { echo 'Backtrace from ' . $type . ' \'' . $errstr . '\' at ' . $errfile . ' ' . $errline . ':' . "\n"; foreach ( $trace as $item ) { echo ' ' . ( isset( $item['file'] ) ? $item['file'] : '<unknown file>' ) . ' ' . ( isset( $item['line'] ) ? $item['line'] : '<unknown line>' ) . ' calling ' . $item['function'] . '()' . "\n"; } flush(); } else if ( ini_get( 'display_errors' ) ) { echo '<p class="error_backtrace">' . "\n"; echo ' Backtrace from ' . $type . ' \'' . $errstr . '\' at ' . $errfile . ' ' . $errline . ':' . "\n"; echo ' <ol>' . "\n"; foreach ( $trace as $item ) { echo ' <li>' . ( isset( $item['file'] ) ? $item['file'] : '<unknown file>' ) . ' ' . ( isset( $item['line'] ) ? $item['line'] : '<unknown line>' ) . ' calling ' . $item['function'] . '()</li>' . "\n"; } echo ' </ol>' . "\n"; echo '</p>' . "\n"; flush(); } if ( ini_get( 'log_errors' ) ) { $items = array(); foreach ( $trace as $item ) { $items[] = ( isset( $item['file'] ) ? $item['file'] : '<unknown file>' ) . ' ' . ( isset( $item['line'] ) ? $item['line'] : '<unknown line>' ) . ' calling ' . $item['function'] . '()'; } $message = 'Backtrace from ' . $type . ' \'' . $errstr . '\' at ' . $errfile . ' ' . $errline . ': ' . join( ' | ', $items ); error_log( $message ); } if ( $fatal ) { exit( 1 ); } } set_error_handler( 'process_error_backtrace' ); /** * Now test whether it all works by uncommenting the below line * * If all is well: * - With WP_DEBUG set to true: You should see a red error notice on your screen * - Independently of the WP_DEBUG setting, the below 'error'-message should have been written to your log file. *Do* check whether it has been.... */ //trigger_error( 'Testing 1..2..3.. Debugging code is working!', E_USER_NOTICE ); }

After you’ve pasted the code in your wp-config.php file, reload your browser. The stack trace should now appear on your screen, copy it and paste it in the support ticket you send to the plugin developer. Please remove the code afterwards from your wp-config.php file! Your stack trace might contain information you don’t want the whole world to know.

I hope this helped you in fixing your White Screen Of Death in WordPress! Found a problem? Got an improvement? Please let me know in the comments below.