diff --git a/reactos/dll/win32/shell32/folders/CDesktopFolder.cpp b/reactos/dll/win32/shell32/folders/CDesktopFolder.cpp
index b9127d4b83f..119ec62c31f 100644
--- a/reactos/dll/win32/shell32/folders/CDesktopFolder.cpp
+++ b/reactos/dll/win32/shell32/folders/CDesktopFolder.cpp
@@ -463,6 +463,12 @@ HRESULT WINAPI CDesktopFolder::BindToStorage(
  */
 HRESULT WINAPI CDesktopFolder::CompareIDs(LPARAM lParam, PCUIDLIST_RELATIVE pidl1, PCUIDLIST_RELATIVE pidl2)
 {
+    if (!pidl1 || !pidl2)
+    {
+        ERR("Got null pidl pointer (%Ix %p %p)!\n", lParam, pidl1, pidl2);
+        return E_INVALIDARG;
+    }
+
     if (_ILIsSpecialFolder(pidl1) || _ILIsSpecialFolder(pidl2))
         return SHELL32_CompareGuidItems(this, lParam, pidl1, pidl2);
 
diff --git a/reactos/dll/win32/shell32/folders/CDrivesFolder.cpp b/reactos/dll/win32/shell32/folders/CDrivesFolder.cpp
index a3b30a39c71..1d38d189c7d 100644
--- a/reactos/dll/win32/shell32/folders/CDrivesFolder.cpp
+++ b/reactos/dll/win32/shell32/folders/CDrivesFolder.cpp
@@ -298,6 +298,12 @@ HRESULT WINAPI CDrivesFolder::BindToStorage(PCUIDLIST_RELATIVE pidl, LPBC pbcRes
 
 HRESULT WINAPI CDrivesFolder::CompareIDs(LPARAM lParam, PCUIDLIST_RELATIVE pidl1, PCUIDLIST_RELATIVE pidl2)
 {
+    if (!pidl1 || !pidl2)
+    {
+        ERR("Got null pidl pointer (%Ix %p %p)!\n", lParam, pidl1, pidl2);
+        return E_INVALIDARG;
+    }
+
     if (_ILIsSpecialFolder(pidl1) || _ILIsSpecialFolder(pidl2))
         return SHELL32_CompareGuidItems(this, lParam, pidl1, pidl2);