If I remove everything YAG related in ext_localconf.php I get a lot of these in backend: PHP Warning PHP Warning: include(/myweb/typo3conf/ext/yag/Configuration/TCA/Album.php): failed to open stream: No such file or directory in /myweb/typo3/sysext/core/Classes/Utility/ExtensionManagementUtility.php line 1815