diff --git a/src/core/slavebase.cpp b/src/core/slavebase.cpp
--- a/src/core/slavebase.cpp
+++ b/src/core/slavebase.cpp
@@ -512,10 +512,10 @@
         if (!d->m_rootEntryListed) {
             qCWarning(KIO_CORE) << "UDSEntry for '.' not found, creating a default one. Please fix the" << QCoreApplication::applicationName() << "KIO slave";
             KIO::UDSEntry entry;
-            entry.insert(KIO::UDSEntry::UDS_NAME, QStringLiteral("."));
-            entry.insert(KIO::UDSEntry::UDS_FILE_TYPE, S_IFDIR);
-            entry.insert(KIO::UDSEntry::UDS_SIZE, 0);
-            entry.insert(KIO::UDSEntry::UDS_ACCESS, S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IXOTH);
+            entry.fastInsert(KIO::UDSEntry::UDS_NAME, QStringLiteral("."));
+            entry.fastInsert(KIO::UDSEntry::UDS_FILE_TYPE, S_IFDIR);
+            entry.fastInsert(KIO::UDSEntry::UDS_SIZE, 0);
+            entry.fastInsert(KIO::UDSEntry::UDS_ACCESS, S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IXOTH);
             d->pendingListEntries.append(entry);
         }