How to fix empty dashboard issue in WordPress?

To fix the bug:

1. Open file blog/wp-admin/includes/screen.php in your favorite text editor.
2. On line 706 find the following PHP statement: <?php echo self::$this->_help_sidebar; ?>
3. Replace it with the statement: <?php echo $this->_help_sidebar; ?>
4. Save your changes.

Hope it helps you.