Class Drupal\dfm\EventSubscriber\DfmSubscriber not found when try to remove the Drupella File Manager

Question

I installed the Drupella File Manager module for Drupal 8.8, but I have Drupal 8.7. I received this error.

Call to undefined method Drupal\Core\File\FileSystem::scanDirectory()

I don't need the module anymore, so I'm trying to remove it. Because of the same error on the uninstall page, I'm trying to manual remove it.

First, I removed dfm (which is the module machine name) from the $module_data configuration as described in Manually disable a module.

Then, I deleted the dfm directory from the /modules directory, but now I receive this error.

Class 'Drupal\dfm\EventSubscriber\DfmSubscriber' not found in Drupal\Component\DependencyInjection\Container->createService() (line 265 of core/lib/Drupal/Component/DependencyInjection/Container.php).

How can I resolve this problem?

Are there other module files that cause problems?

Clearing the cache doesn't help.

Answer 1

Ok, I commented the line that causes the first error and then uninstalled the module via the uninstall page