Edit file File name : org.gnome.desktop.thumbnailers.gschema.xml Content :<?xml version="1.0" encoding="UTF-8"?> <schemalist gettext-domain="gsettings-desktop-schemas"> <schema id="org.gnome.desktop.thumbnailers" path="/org/gnome/desktop/thumbnailers/"> <key name="disable-all" type="b"> <default>false</default> <summary>Disable all external thumbnailers</summary> <description> Set to true to disable all external thumbnailer programs, independent on whether they are independently disabled/enabled. </description> </key> <key name="disable" type="as"> <default>[]</default> <summary> List of mime-types for which external thumbnailer programs will be disabled </summary> <description> Thumbnails will not be created for files whose mime-type is contained in the list. </description> </key> </schema> </schemalist> Save