Today I ran into an issue where running the command:
      
    drush status
ended with this error: 
Drush command terminated abnormally due to an unrecoverable error..
Not sure what was causing this problem so I turned to Google and came across this post: http://drupal.org/node/1140842. This comment, http://drupal.org/node/1140842#comment-4526230, mentioned that they were using mobile tools, which I was, and when they disabled it, drush began working again. Unfortunately, this website was relying pretty heavily on mobile tools, and therefore I couldn't just disable that module.