Index: reactos/dll/shellext/acppage/CLayerUIPropPage.cpp
===================================================================
--- reactos/dll/shellext/acppage/CLayerUIPropPage.cpp	(revision 75532)
+++ reactos/dll/shellext/acppage/CLayerUIPropPage.cpp	(working copy)
@@ -158,6 +158,27 @@
         }
         return InitFile(Buffer);
     }
+
+    CString tmp;
+    if (tmp.GetEnvironmentVariable(L"SystemRoot"))
+    {
+        tmp += L"\\System32";
+        if (ExpandedFilename.GetLength() >= tmp.GetLength() &&
+            ExpandedFilename.Left(tmp.GetLength()).MakeLower() == tmp.MakeLower())
+        {
+            ACDBG(L"Ignoring System32: %s\r\n", (PCWSTR)ExpandedFilename);
+            return E_FAIL;
+        }
+        tmp.GetEnvironmentVariable(L"SystemRoot");
+        tmp += L"\\WinSxs";
+        if (ExpandedFilename.GetLength() >= tmp.GetLength() &&
+            ExpandedFilename.Left(tmp.GetLength()).MakeLower() == tmp.MakeLower())
+        {
+            ACDBG(L"Ignoring WinSxs: %s\r\n", (PCWSTR)ExpandedFilename);
+            return E_FAIL;
+        }
+    }
+
     for (size_t n = 0; g_AllowedExtensions[n]; ++n)
     {
         if (!wcsicmp(g_AllowedExtensions[n], pwszExt))
Index: reactos/sdk/lib/atl/atlsimpstr.h
===================================================================
--- reactos/sdk/lib/atl/atlsimpstr.h	(revision 75532)
+++ reactos/sdk/lib/atl/atlsimpstr.h	(working copy)
@@ -162,9 +162,8 @@
         int nLength = StringLength(pszSrc);
         CStringData* pData = pStringMgr->Allocate(nLength, sizeof(XCHAR));
         if (pData == NULL)
-        {
-            throw; // ThrowMemoryException();
-        }
+            ThrowMemoryException();
+
         Attach(pData);
         SetLength(nLength);
         CopyChars(m_pszData, nLength, pszSrc, nLength);
@@ -176,12 +175,12 @@
         _Inout_ IAtlStringMgr* pStringMgr)
     {
         if (pchSrc == NULL && nLength != 0)
-            throw;
+            ThrowInvalidArgException();
 
         CStringData* pData = pStringMgr->Allocate(nLength, sizeof(XCHAR));
         if (pData == NULL)
         {
-            throw; // ThrowMemoryException();
+            ThrowMemoryException();
         }
         Attach(pData);
         SetLength(nLength);
@@ -615,6 +614,11 @@
         AtlThrow(E_OUTOFMEMORY);
     }
 
+    static void ThrowInvalidArgException()
+    {
+        AtlThrow(E_INVALIDARG);
+    }
+
 };
 
 #ifdef UNICODE