diff --git a/reactos/ntoskrnl/io/pnpmgr/pnpnotify.c b/reactos/ntoskrnl/io/pnpmgr/pnpnotify.c
index c328c80965f..f19f986e4e3 100644
--- a/reactos/ntoskrnl/io/pnpmgr/pnpnotify.c
+++ b/reactos/ntoskrnl/io/pnpmgr/pnpnotify.c
@@ -42,6 +42,8 @@ IopNotifyPlugPlayNotification(
 	PLIST_ENTRY ListEntry;
 	PVOID NotificationStructure;
 	BOOLEAN CallCurrentEntry;
+	UNICODE_STRING GuidString;
+	NTSTATUS Status;
 
 	ASSERT(DeviceObject);
 
@@ -71,6 +73,13 @@ IopNotifyPlugPlayNotification(
 			RtlCopyMemory(&NotificationInfos->Event, Event, sizeof(GUID));
 			RtlCopyMemory(&NotificationInfos->InterfaceClassGuid, EventCategoryData1, sizeof(GUID));
 			NotificationInfos->SymbolicLinkName = (PUNICODE_STRING)EventCategoryData2;
+			Status = RtlStringFromGUID(&NotificationInfos->InterfaceClassGuid, &GuidString);
+			if (!NT_SUCCESS(Status))
+			{
+				KeReleaseGuardedMutex(&PnpNotifyListLock);
+				ExFreePool(NotificationStructure);
+				return;
+			}
 			break;
 		}
 		case EventCategoryHardwareProfileChange:
@@ -125,12 +134,17 @@ IopNotifyPlugPlayNotification(
 		ChangeEntry = CONTAINING_RECORD(ListEntry, PNP_NOTIFY_ENTRY, PnpNotifyList);
 		CallCurrentEntry = FALSE;
 
+		if (ChangeEntry->EventCategory != EventCategory)
+		{
+			ListEntry = ListEntry->Flink;
+			continue;
+		}
+
 		switch (EventCategory)
 		{
 			case EventCategoryDeviceInterfaceChange:
 			{
-				if (ChangeEntry->EventCategory == EventCategory
-					&& RtlCompareUnicodeString(&ChangeEntry->Guid, (PUNICODE_STRING)EventCategoryData1, FALSE) == 0)
+				if (RtlCompareUnicodeString(&ChangeEntry->Guid, &GuidString, FALSE) == 0)
 				{
 					CallCurrentEntry = TRUE;
 				}
@@ -174,6 +188,8 @@ IopNotifyPlugPlayNotification(
 	}
 	KeReleaseGuardedMutex(&PnpNotifyListLock);
 	ExFreePoolWithTag(NotificationStructure, TAG_PNP_NOTIFY);
+	if (EventCategory == EventCategoryDeviceInterfaceChange)
+		RtlFreeUnicodeString(&GuidString);
 }
 
 /* PUBLIC FUNCTIONS **********************************************************/