A recent update of gallery2 removed 3 modules, which, if these had not been deactivated within gallery2 beforehand, caused errors in upgraded gallery2 installations. To remove the remnants of the recently removed uploadapplet, slideshowapplet and remote modules, do the following: In your gallery2 database: delete from g2_PluginMap where g_pluginId = 'uploadapplet'; delete from g2_PluginPackageMap where g_pluginId = 'uploadapplet'; delete from g2_PluginParameterMap where g_pluginId = 'uploadapplet'; delete from g2_PluginMap where g_pluginId = 'slideshowapplet'; delete from g2_PluginPackageMap where g_pluginId = 'slideshowapplet'; delete from g2_PluginParameterMap where g_pluginId = 'slideshowapplet'; delete from g2_PluginMap where g_pluginId = 'remote'; delete from g2_PluginPackageMap where g_pluginId = 'remote'; delete from g2_PluginParameterMap where g_pluginId = 'remote'; Then, on the host with gallery2 installed, in your g2data directory: rm -f g2data/cache/module/_all/0/0/* rm -rf g2data/cache/module/uploadapplet rm -rf g2data/cache/module/slideshowapplet rm -rf g2data/cache/module/remote This will restore any functionality not directly affected by the .jar removals, such as adding new items.