diff --git a/src/propertyinfo.h b/src/propertyinfo.h
--- a/src/propertyinfo.h
+++ b/src/propertyinfo.h
@@ -41,6 +41,7 @@
 class KFILEMETADATA_EXPORT PropertyInfo
 {
 public:
+    PropertyInfo();
     PropertyInfo(Property::Property property);
     PropertyInfo(const PropertyInfo& pi);
     ~PropertyInfo();
@@ -97,5 +98,8 @@
     Private* d;
 };
 
-}
+} // namespace
+Q_DECLARE_METATYPE(KFileMetaData::PropertyInfo)
+
+
 #endif // _KFILEMETADATA_PROPERTYINFO_H
diff --git a/src/propertyinfo.cpp b/src/propertyinfo.cpp
--- a/src/propertyinfo.cpp
+++ b/src/propertyinfo.cpp
@@ -39,6 +39,16 @@
     QString (*formatAsString)(const QVariant& value) = nullptr;
 };
 
+PropertyInfo::PropertyInfo()
+    : d(new Private)
+{
+    d->prop = Property::Empty;
+    d->name = QStringLiteral("empty");
+    d->valueType = QVariant::Invalid;
+    d->shouldBeIndexed = false;
+    d->formatAsString = &FormatStrings::toStringFunction;
+}
+
 PropertyInfo::PropertyInfo(Property::Property property)
     : d(new Private)
 {