I did a Drupal 7 update using drush up and received the following message, repeated numerous times:

Unknown engine type outputformat

Since that update, Drush does not work, but rather returns the same message.

How can I fix this problem?

I have Drupal 7.52 and Drush 5.9.

  • 2
    Drush 5.9 was released over three years ago and is unsupported by its maintainers.
    – mona lisa
    Commented Nov 26, 2016 at 18:20

3 Answers 3


You can install drush to latest version or specified version. I prefer drush 7, you can make this, first uninstall the current version of drush of your server.

i use debian, then i install with

sudo apt-get install drush

and you need remove

sudo apt-get remove drush

and later install again with composer

curl -sS https://getcomposer.org/installer | php
sudo mv composer.phar /usr/local/bin/composer
sudo ln -s /usr/local/bin/composer /usr/bin/composer

sudo git clone https://github.com/drush-ops/drush.git /usr/local/src/drush
cd /usr/local/src/drush
sudo git checkout 7.0.0  #or whatever version you want.
sudo ln -s /usr/local/src/drush/drush /usr/bin/drush
sudo composer install
drush --version

and ready to use drush version 7


Drush 5.9 is very out of date (the current stable version is 8.1.7) and if you updated Drupal several versions very likely broke because of a change long-since accounted for in new versions. There was an issue with similar symptoms reported in 2013 that was resolvable by clearing drush's cache (drush cc drush), but the real fix is move to a newer version of drush.

There are several upgrade paths depending on your setup, and how drush was installed the first time. For options see How to Upgrade Drush on Drupal.org and the official drush install directions.

  • Acrosman, Thanks! All of my other sites are working fine with the old 5.9, but I guess its time to clean'em up and give them the latest drush ... can't live without it. Your SOLUTION worked! Thanks! [now look over your shoulder ... I was brought up in Florence many moons ago, and lived all over the world since then. Best - Carl
    – cfusch
    Commented Nov 27, 2016 at 18:22

drush 5.x and below fails with multiple Unknown engine type outputformat error messages when the Missing Message Fixer module is active. This module was developed specifically to deal with a problem that appeared when upgrading to Drupal 7.50. It's mentioned in the module's homepage:

If you are stuck on an old version of Drush (5.x and below). If this module is enabled and you try to run any drush commands, you may get: Unknown engine type outputformat. I would recommend updating your drush or using the GUI version of this module and disabling the module

To me, disabling the module is the solution. Some people get drush as a package of LTS Linux distros such as Debian 7 (ships drush 5.4), Debian 8 or Ubuntu 14.04 (ship drush 5.10), and forcing them to upgrade to the newest is inconsistent with the concept of LTS releases, where every package must be maintained typically for 5 years.

  • I did fix Module Missing Message Fixer so it no longer outputs this Unknown engine type outputformat
    – John O
    Commented May 11, 2017 at 21:11
  • Thank you Daniel. This fixed the issue for me. I am still seeing "Unknown engine type outputformat" in my terminal. However, Drush is now able to run and install updates before it outputs "Unknown engine type outputformat".
    – arnoldbird
    Commented Oct 3, 2017 at 17:48

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