Magento 2: Plugin class Magento\ThemeSampleData\Plugin\View\Page\Config doesn't exist

[sneakingJ]

The box worked great the first time I ran it. Had to create an own admin account and the backend is only reachable with /adminpanel instead of /admin_dev. I didn't change anything afterwards. Now I get the the following error everytime I start the box up:

1 exception(s):
Exception #0 (InvalidArgumentException): Plugin class Magento\ThemeSampleData\Plugin\View\Page\Config doesn't exist

Exception #0 (InvalidArgumentException): Plugin class Magento\ThemeSampleData\Plugin\View\Page\Config doesn't exist
#0 /var/www/public/magento2/vendor/magento/framework/Interception/PluginList/PluginList.php(268): Magento\Framework\Interception\PluginList\PluginList->_inheritPlugins('Magento\\Framewo...')
#1 /var/www/public/magento2/generated/code/Magento/Framework/View/Page/Config/Interceptor.php(308): Magento\Framework\Interception\PluginList\PluginList->getNext('Magento\\Framewo...', 'setElementAttri...')
#2 /var/www/public/magento2/vendor/magento/framework/View/Page/Config.php(176): Magento\Framework\View\Page\Config\Interceptor->setElementAttribute('html', 'lang', 'en-US')
#3 /var/www/public/magento2/generated/code/Magento/Framework/View/Page/Config/Interceptor.php(14): Magento\Framework\View\Page\Config->__construct(Object(Magento\Framework\View\Asset\Repository), Object(Magento\Framework\View\Asset\GroupedCollection), Object(Magento\Framework\App\Config), Object(Magento\Theme\Model\Favicon\Favicon), Object(Magento\Framework\View\Page\Title), Object(Magento\Framework\Locale\Resolver), true)
#4 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php(111): Magento\Framework\View\Page\Config\Interceptor->__construct(Object(Magento\Framework\View\Asset\Repository), Object(Magento\Framework\View\Asset\GroupedCollection), Object(Magento\Framework\App\Config), Object(Magento\Theme\Model\Favicon\Favicon), Object(Magento\Framework\View\Page\Title), Object(Magento\Framework\Locale\Resolver), true)
#5 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(108): Magento\Framework\ObjectManager\Factory\AbstractFactory->createObject('Magento\\Framewo...', Array)
#6 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(150): Magento\Framework\ObjectManager\Factory\Compiled->create('Magento\\Framewo...')
#7 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(79): Magento\Framework\ObjectManager\Factory\Compiled->get('Magento\\Framewo...')
#8 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(150): Magento\Framework\ObjectManager\Factory\Compiled->create('Magento\\Framewo...')
#9 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(125): Magento\Framework\ObjectManager\Factory\Compiled->get('Magento\\Framewo...')
#10 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(86): Magento\Framework\ObjectManager\Factory\Compiled->parseArray(Array)
#11 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(150): Magento\Framework\ObjectManager\Factory\Compiled->create('Magento\\Framewo...')
#12 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(79): Magento\Framework\ObjectManager\Factory\Compiled->get('Magento\\Framewo...')
#13 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(150): Magento\Framework\ObjectManager\Factory\Compiled->create('Magento\\Framewo...')
#14 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(79): Magento\Framework\ObjectManager\Factory\Compiled->get('Magento\\Framewo...')
#15 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(150): Magento\Framework\ObjectManager\Factory\Compiled->create('Magento\\Framewo...')
#16 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(79): Magento\Framework\ObjectManager\Factory\Compiled->get('Magento\\Framewo...')
#17 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(150): Magento\Framework\ObjectManager\Factory\Compiled->create('Magento\\Framewo...')
#18 /var/www/public/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(79): Magento\Framework\ObjectManager\Factory\Compiled->get('Magento\\Framewo...')
#19 /var/www/public/magento2/vendor/magento/framework/ObjectManager/ObjectManager.php(56): Magento\Framework\ObjectManager\Factory\Compiled->create('Magento\\Cms\\Con...', Array)
#20 /var/www/public/magento2/vendor/magento/framework/App/ActionFactory.php(40): Magento\Framework\ObjectManager\ObjectManager->create('Magento\\Cms\\Con...')
#21 /var/www/public/magento2/vendor/magento/framework/App/Router/Base.php(297): Magento\Framework\App\ActionFactory->create('Magento\\Cms\\Con...')
#22 /var/www/public/magento2/vendor/magento/framework/App/Router/Base.php(158): Magento\Framework\App\Router\Base->matchAction(Object(Magento\Framework\App\Request\Http), Array)
#23 /var/www/public/magento2/vendor/magento/framework/App/FrontController.php(50): Magento\Framework\App\Router\Base->match(Object(Magento\Framework\App\Request\Http))
#24 /var/www/public/magento2/vendor/magento/framework/Interception/Interceptor.php(58): Magento\Framework\App\FrontController->dispatch(Object(Magento\Framework\App\Request\Http))
#25 /var/www/public/magento2/vendor/magento/framework/Interception/Interceptor.php(138): Magento\Framework\App\FrontController\Interceptor->___callParent('dispatch', Array)
#26 /var/www/public/magento2/vendor/magento/module-store/App/FrontController/Plugin/RequestPreprocessor.php(94): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#27 /var/www/public/magento2/vendor/magento/framework/Interception/Interceptor.php(135): Magento\Store\App\FrontController\Plugin\RequestPreprocessor->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#28 /var/www/public/magento2/vendor/magento/module-page-cache/Model/App/FrontController/BuiltinPlugin.php(73): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#29 /var/www/public/magento2/vendor/magento/framework/Interception/Interceptor.php(135): Magento\PageCache\Model\App\FrontController\BuiltinPlugin->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#30 /var/www/public/magento2/vendor/magento/framework/Interception/Interceptor.php(153): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#31 /var/www/public/magento2/generated/code/Magento/Framework/App/FrontController/Interceptor.php(26): Magento\Framework\App\FrontController\Interceptor->___callPlugins('dispatch', Array, NULL)
#32 /var/www/public/magento2/vendor/magento/framework/App/Http.php(135): Magento\Framework\App\FrontController\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
#33 /var/www/public/magento2/vendor/magento/framework/App/Bootstrap.php(256): Magento\Framework\App\Http->launch()
#34 /var/www/public/magento2/index.php(39): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http))
#35 {main}

Even after vagrant destroy and restarting the box with vagrant up, Magento 2 always produces this error right in the beginning.

Magento 1 is still working though.