diff --git a/autotests/kfileitemtest.cpp b/autotests/kfileitemtest.cpp
--- a/autotests/kfileitemtest.cpp
+++ b/autotests/kfileitemtest.cpp
@@ -30,6 +30,7 @@
 #include "kiotesthelper.h"
 
 #include <QMimeDatabase>
+#include <KProtocolInfo>
 
 QTEST_MAIN(KFileItemTest)
 
@@ -620,7 +621,18 @@
     QTest::newRow("relative") << QUrl("foo") << "unknown";
     QTest::newRow("tilde") << QUrl("~") << "unknown";
 
-    // TODO more tests
+    QTest::newRow("unknownscheme folder") << QUrl("unknownscheme:/") << "inode-directory";
+    QTest::newRow("unknownscheme file") << QUrl("unknownscheme:/test") << "application-octet-stream";
+
+    QTest::newRow("trash folder") << QUrl("trash:/") << "user-trash-full";
+    QTest::newRow("trash file") << QUrl("trash:/test") << "user-trash-full";
+
+    QTest::newRow("https scheme") << QUrl("https://kde.org/") << "text-html";
+
+    if (KProtocolInfo::isKnownProtocol("smb")) {
+        QTest::newRow("smb folder") << QUrl("smb:/") << "network-workgroup";
+        QTest::newRow("smb file") << QUrl("smb:/test") << "network-workgroup";
+    }
 }
 
 void KFileItemTest::testIconNameForUrl()
diff --git a/src/core/global.cpp b/src/core/global.cpp
--- a/src/core/global.cpp
+++ b/src/core/global.cpp
@@ -223,55 +223,51 @@
 
 QString KIO::iconNameForUrl(const QUrl &url)
 {
-    const QLatin1String unknown("unknown");
     if (url.scheme().isEmpty()) { // empty URL or relative URL (e.g. '~')
-        return unknown;
+        return QStringLiteral("unknown");
     }
     QMimeDatabase db;
     const QMimeType mt = db.mimeTypeForUrl(url);
-    const QString mimeTypeIcon = mt.iconName();
-    QString i = mimeTypeIcon;
+    QString iconName;
 
     if (url.isLocalFile()) {
         // Check to see whether it's an xdg location (e.g. Pictures folder)
         if (mt.inherits(QStringLiteral("inode/directory"))) {
-            i = KIOPrivate::iconForStandardPath(url.toLocalFile());
+            iconName = KIOPrivate::iconForStandardPath(url.toLocalFile());
         }
 
         // Let KFileItem::iconName handle things for us
-        if (i == unknown || i.isEmpty() || mt.isDefault()) {
+        if (iconName.isEmpty()) {
             const KFileItem item(url, mt.name());
-            i = item.iconName();
+            iconName = item.iconName();
         }
 
     } else {
         // It's non-local and maybe on a slow filesystem
 
         // Look for a favicon
         if (url.scheme().startsWith(QLatin1String("http"))) {
-            i = favIconForUrl(url);
+            iconName = favIconForUrl(url);
         }
 
         // Then handle the trash
         else if (url.scheme() == QLatin1String("trash") && url.path().length() <= 1) {
             KConfig trashConfig(QStringLiteral("trashrc"), KConfig::SimpleConfig);
             if (trashConfig.group("Status").readEntry("Empty", true)) {
-                i = QStringLiteral("user-trash");
+                iconName = QStringLiteral("user-trash");
             } else {
-                i = QStringLiteral("user-trash-full");
+                iconName = QStringLiteral("user-trash-full");
             }
         }
 
-        if (i.isEmpty()) {
-            i = KProtocolInfo::icon(url.scheme());
-        }
-
-        // root of protocol: if we found nothing, revert to mimeTypeIcon (which is usually "folder")
-        if (url.path().length() <= 1 && (i == unknown || i.isEmpty())) {
-            i = mimeTypeIcon;
+        // and other protocols
+        if (iconName.isEmpty()) {
+            iconName = KProtocolInfo::icon(url.scheme());
         }
     }
-    return !i.isEmpty() ? i : unknown;
+    // if we found nothing, return QMimeType.iconName()
+    // (which fallbacks to "application-octet-stream" when no mimetype could be determined)
+    return !iconName.isEmpty() ? iconName : mt.iconName();
 }
 
 QUrl KIO::upUrl(const QUrl &url)