After I tried to update the database I got the following error:

Failed: Drupal\Component\Plugin\Exception\PluginNotFoundException:
[error] The "pdf_thumbnail" plugin does not exist. in Drupal\Core\Plugin\DefaultPluginManager->doGetDefinition() (line 52 of /home/www/sites/stdev/web/core/lib/Drupal/Component/Plugin/Discovery/DiscoveryTrait.php).

I tried to find the solution and found one of a similar issue:

drush updb fails with "the 'media_delete_action' plugin does not exist" after 8.4.6 > 8.5.1 update

Alas, I can't apply that solution because I don't know which module uses the pdf_thumbnail plugin. How can I find it out which module uses the plugin and solve the problem with the update?

  • Have you try update entities and db drush entity-updates drush updb ?.
    – berramou
    Commented Sep 17, 2018 at 16:52
  • I've just tried but to no avail.
    – Rusletov
    Commented Sep 18, 2018 at 11:18
  • Did you uninstall any module use this plugin_id pdf_thumbnail before.
    – berramou
    Commented Sep 18, 2018 at 11:32
  • Sorry, not sure I get it. I didn't uninstall any module. I did take an existing site and updated it with Composer update --with-dependencies. Then I ran "Drush updb -y" and got that message about the pdf_thumbnail plugin.
    – Rusletov
    Commented Sep 18, 2018 at 11:49
  • 1
    I am also seeing this bug. Other updates are not being run as a result.
    – jhchnc
    Commented Oct 19, 2018 at 22:37

1 Answer 1


I resolved this by first re-enabling the PDF module, and then by updating core.

In my composer setup, the PDF module was a git submodule. However, my shared host would not work with that. So, I removed the cached information

git rm --cached web/modules/contrib/pdf

And then I added the code in that directory to my main repo.

Next, enable the PDF module.

Finally, proceed with the update process, and run update.php or drush updb

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