Fatal error on Drush run I've installed Drush following http://www.zyxware.com/articles/4497/drupal-installing-latest-version-of-drush-on-linux-system-and-troubleshooting.

Now, when I try to run Drush, I get this error message.


  PHP Fatal error: Class Symfony\Component\Console\Style\SymfonyStyle contains 4 abstract methods and must therefore be declared abstract or implement the remaining methods (Symfony\Component\Console\Output\OutputInterface::isQuiet, Symfony\Component\Console\Output\OutputInterface::isVerbose, Symfony\Component\Console\Output\OutputInterface::isVeryVerbose, ...) in /var/www/html/tubimer/vendor/symfony/console/Style/SymfonyStyle.php on line 33
  Drush command terminated abnormally due to an unrecoverable error.
  Error: Class Symfony\Component\Console\Style\SymfonyStyle contains 4 abstract methods and must therefore be declared abstract or implement the remaining methods (Symfony\Component\Console\Output\OutputInterface::isQuiet, Symfony\Component\Console\Output\OutputInterface::isVerbose, Symfony\Component\Console\Output\OutputInterface::isVeryVerbose, ...) in /var/www/html/tubimer/vendor/symfony/console/Style/SymfonyStyle.php, line 33


How do I fix these errors?
I suggest you to run -

composer self-update
composer update


It might solve your problem, but if it doesn't then try to install latest version of drush. I installed drush using https://www.drupal.org/node/1248790.
However, there is a full documentation on how to install drush for specific operating system. Link to documentation - https://www.drupal.org/node/1791676