diff --git a/dlls/fltlib/fltlib.c b/dlls/fltlib/fltlib.c
index 9975a290601..50f46accf53 100644
--- a/dlls/fltlib/fltlib.c
+++ b/dlls/fltlib/fltlib.c
@@ -65,7 +65,7 @@ HRESULT WINAPI FilterConnectCommunicationPort(LPCWSTR lpPortName, DWORD dwOption
 HRESULT WINAPI FilterFindFirst(DWORD class, LPVOID buffer, DWORD size, LPDWORD bytes_returned,
                                LPHANDLE handle)
 {
-    FIXME("%u, %p, %u, %p, %p\n", class, buffer, size, bytes_returned, handle);
+    FIXME("(%u, %p, %u, %p, %p) stub\n", class, buffer, size, bytes_returned, handle);
     return HRESULT_FROM_WIN32(ERROR_NO_MORE_ITEMS);
 }
 
@@ -74,6 +74,19 @@ HRESULT WINAPI FilterFindFirst(DWORD class, LPVOID buffer, DWORD size, LPDWORD b
  */
 HRESULT WINAPI FilterFindClose(HANDLE handle)
 {
-    FIXME("%p\n", handle);
+    FIXME("(%p) stub\n", handle);
+    return S_OK;
+}
+
+/**********************************************************************
+ *      FilterUnload            (FLTLIB.@)
+ */
+HRESULT WINAPI FilterUnload(LPCWSTR lpFilterName)
+{
+    FIXME("(%s) stub\n", debugstr_w(lpFilterName));
+
+    if (!lpFilterName)
+        return HRESULT_FROM_WIN32(ERROR_INVALID_PARAMETER);
+
     return S_OK;
 }
diff --git a/dlls/fltlib/fltlib.spec b/dlls/fltlib/fltlib.spec
index ecf5893fe76..91e803be009 100644
--- a/dlls/fltlib/fltlib.spec
+++ b/dlls/fltlib/fltlib.spec
@@ -19,7 +19,7 @@
 @ stub FilterLoad
 @ stub FilterReplyMessage
 @ stub FilterSendMessage
-@ stub FilterUnload
+@ stdcall FilterUnload(wstr)
 @ stub FilterVolumeClose
 @ stub FilterVolumeFindClose
 @ stub FilterVolumeFindFirst