diff --git a/dll/shellext/ntobjshex/ntobjfolder.cpp b/dll/shellext/ntobjshex/ntobjfolder.cpp
index 056bf67ca8..899edb382d 100644
--- a/dll/shellext/ntobjshex/ntobjfolder.cpp
+++ b/dll/shellext/ntobjshex/ntobjfolder.cpp
@@ -484,6 +484,12 @@ HRESULT CNtObjectFolder::GetInfoFromPidl(LPCITEMIDLIST pcidl, const NtPidlEntry
 {
     NtPidlEntry * entry = (NtPidlEntry*) &(pcidl->mkid);
 
+    if(!entry)
+    {
+        DbgPrint("PCIDL with NULL mkid\n");
+        return E_INVALIDARG;
+    }
+
     if (entry->cb < sizeof(NtPidlEntry))
     {
         DbgPrint("PCIDL too small %l (required %l)\n", entry->cb, sizeof(NtPidlEntry));
diff --git a/dll/shellext/ntobjshex/regfolder.cpp b/dll/shellext/ntobjshex/regfolder.cpp
index 70f1575d51..80916fea14 100644
--- a/dll/shellext/ntobjshex/regfolder.cpp
+++ b/dll/shellext/ntobjshex/regfolder.cpp
@@ -428,6 +428,12 @@ HRESULT CRegistryFolder::GetInfoFromPidl(LPCITEMIDLIST pcidl, const RegPidlEntry
 {
     RegPidlEntry * entry = (RegPidlEntry*) &(pcidl->mkid);
 
+    if(!entry)
+    {
+        DbgPrint("PCIDL with NULL mkid\n");
+        return E_INVALIDARG;
+    }
+
     if (entry->cb < sizeof(RegPidlEntry))
     {
         DbgPrint("PCIDL too small %l (required %l)\n", entry->cb, sizeof(RegPidlEntry));