diff --git a/src/corelib/io/qdir.cpp b/src/corelib/io/qdir.cpp
index 62dae3577c..47fac66c4f 100644
--- a/src/corelib/io/qdir.cpp
+++ b/src/corelib/io/qdir.cpp
@@ -947,6 +947,12 @@ QString QDir::fromNativeSeparators(const QString &pathName)
     int i = pathName.indexOf(QLatin1Char('\\'));
     if (i != -1) {
         QString n(pathName);
+        if (n.startsWith(QLatin1String("\\\\?\\"))) {
+            n.remove(0, 4);
+            i = n.indexOf(QLatin1Char('\\'));
+            if (i == -1)
+                return n;
+        }
 
         QChar * const data = n.data();
         data[i++] = QLatin1Char('/');
@@ -2339,6 +2345,11 @@ static QString qt_cleanPath(const QString &path, bool *ok)
     if (path.isEmpty())
         return path;
     QString name = path;
+#if defined (Q_OS_WIN)
+    if (name.startsWith(QLatin1String("\\\\?\\")))
+        name.remove(0, 4);
+#endif
+
     QChar dir_separator = QDir::separator();
     if (dir_separator != QLatin1Char('/'))
        name.replace(dir_separator, QLatin1Char('/'));
diff --git a/tests/auto/corelib/io/qdir/tst_qdir.cpp b/tests/auto/corelib/io/qdir/tst_qdir.cpp
index 2aebc67dcf..52e7ebadb1 100644
--- a/tests/auto/corelib/io/qdir/tst_qdir.cpp
+++ b/tests/auto/corelib/io/qdir/tst_qdir.cpp
@@ -1268,6 +1268,7 @@ tst_QDir::cleanPath_data()
     QTest::newRow("drive-above-root") << "A:/.." << "A:/..";
     QTest::newRow("unc-server-up") << "//server/path/.." << "//server";
     QTest::newRow("unc-server-above-root") << "//server/.." << "//server/..";
+    QTest::newRow("longpath") << "\\\\?\\d:\\" << "d:/";
 #else
     QTest::newRow("data15") << "//c:/foo" << "/c:/foo";
 #endif // non-windows
@@ -1745,6 +1746,7 @@ void tst_QDir::nativeSeparators()
     QCOMPARE(QDir::toNativeSeparators(QLatin1String("\\")), QString("\\"));
     QCOMPARE(QDir::fromNativeSeparators(QLatin1String("/")), QString("/"));
     QCOMPARE(QDir::fromNativeSeparators(QLatin1String("\\")), QString("/"));
+    QCOMPARE(QDir::fromNativeSeparators(QLatin1String("\\\\?\\C:\\")), QString("C:/"));
 #else
     QCOMPARE(QDir::toNativeSeparators(QLatin1String("/")), QString("/"));
     QCOMPARE(QDir::toNativeSeparators(QLatin1String("\\")), QString("\\"));