Faced this problem today. Could not find the cause or even a solution online. I did a quick fix, not sure how this is going to affect me later. If anyone has a better solution, do share. Thanks.
Got this error while trying to list the users FatalErrorException: Error: Class 'Sonata\AdminBundle\Form\Type\BooleanType' not found in ..vendor\sonata-project\doctrine-orm-admin-bundle\Sonata\DoctrineORMAdminBundle\Filter\BooleanFilter.php
What I did to fix it was to change {#vendor\sonata-project\doctrine-orm-admin-bundle\Sonata\DoctrineORMAdminBundle\Filter\BooleanFilter.php#}use Sonata\AdminBundle\Form\Type\BooleanType;use Sonata\CoreBundle\Form\Type\BooleanType;use Sonata\AdminBundle\Datagrid\ProxyQueryInterface;