diff --git a/konq-plugins/arkplugin/arkplugin.cpp b/konq-plugins/arkplugin/arkplugin.cpp
index 1295ada..97513b8 100644
--- a/konq-plugins/arkplugin/arkplugin.cpp
+++ b/konq-plugins/arkplugin/arkplugin.cpp
@@ -285,14 +285,14 @@ void ArkMenu::compMimeTypes()
     }
 
     bool havelzma = false;
-    if ( !KStandardDirs::findExe( "lzma" ).isNull() && m_conf->readBoolEntry( "UseLzma", false ) )
+    if ( !KStandardDirs::findExe( "lzma" ).isNull() && m_conf->readBoolEntry( "UseLzma", true ) )
     {
         havelzma = true;
         m_archiveMimeTypes << "application/x-lzma";
     }
 
     bool havexz = false;
-    if ( !KStandardDirs::findExe( "xz" ).isNull() && m_conf->readBoolEntry( "UseXz", false ) )
+    if ( !KStandardDirs::findExe( "xz" ).isNull() && m_conf->readBoolEntry( "UseXz", true ) )
     {
         havexz = true;
         m_archiveMimeTypes << "application/x-xz";