diff --git a/dlls/ole32/compobj.c b/dlls/ole32/compobj.c
index b8954fb5480..4d791f4d54c 100644
--- a/dlls/ole32/compobj.c
+++ b/dlls/ole32/compobj.c
@@ -2066,6 +2066,36 @@ static HRESULT __CLSIDFromString(LPCWSTR s, LPCLSID id)
 
 /*****************************************************************************/
 
+static HRESULT clsid_from_string_reg(LPCOLESTR progid, CLSID *clsid)
+{
+    static const WCHAR clsidW[] = { '\\','C','L','S','I','D',0 };
+    WCHAR buf2[CHARS_IN_GUID];
+    LONG buf2len = sizeof(buf2);
+    HKEY xhkey;
+    WCHAR *buf;
+
+    memset(clsid, 0, sizeof(*clsid));
+    buf = HeapAlloc( GetProcessHeap(),0,(strlenW(progid)+8) * sizeof(WCHAR) );
+    strcpyW( buf, progid );
+    strcatW( buf, clsidW );
+    if (open_classes_key(HKEY_CLASSES_ROOT, buf, MAXIMUM_ALLOWED, &xhkey))
+    {
+        HeapFree(GetProcessHeap(),0,buf);
+        WARN("couldn't open key for ProgID %s\n", debugstr_w(progid));
+        return CO_E_CLASSSTRING;
+    }
+    HeapFree(GetProcessHeap(),0,buf);
+
+    if (RegQueryValueW(xhkey,NULL,buf2,&buf2len))
+    {
+        RegCloseKey(xhkey);
+        WARN("couldn't query clsid value for ProgID %s\n", debugstr_w(progid));
+        return CO_E_CLASSSTRING;
+    }
+    RegCloseKey(xhkey);
+    return __CLSIDFromString(buf2,clsid);
+}
+
 HRESULT WINAPI CLSIDFromString(LPCOLESTR idstr, LPCLSID id )
 {
     HRESULT ret;
@@ -2076,7 +2106,7 @@ HRESULT WINAPI CLSIDFromString(LPCOLESTR idstr, LPCLSID id )
     ret = __CLSIDFromString(idstr, id);
     if(ret != S_OK) { /* It appears a ProgID is also valid */
         CLSID tmp_id;
-        ret = CLSIDFromProgID(idstr, &tmp_id);
+        ret = clsid_from_string_reg(idstr, &tmp_id);
         if(SUCCEEDED(ret))
             *id = tmp_id;
     }
@@ -2301,40 +2331,13 @@ HRESULT WINAPI ProgIDFromCLSID(REFCLSID clsid, LPOLESTR *ppszProgID)
  */
 HRESULT WINAPI CLSIDFromProgID(LPCOLESTR progid, LPCLSID clsid)
 {
-    static const WCHAR clsidW[] = { '\\','C','L','S','I','D',0 };
-    WCHAR buf2[CHARS_IN_GUID];
-    LONG buf2len = sizeof(buf2);
-    HKEY xhkey;
-    WCHAR *buf;
-
     if (!progid || !clsid)
     {
         ERR("neither progid (%p) nor clsid (%p) are optional\n", progid, clsid);
         return E_INVALIDARG;
     }
 
-    /* initialise clsid in case of failure */
-    memset(clsid, 0, sizeof(*clsid));
-
-    buf = HeapAlloc( GetProcessHeap(),0,(strlenW(progid)+8) * sizeof(WCHAR) );
-    strcpyW( buf, progid );
-    strcatW( buf, clsidW );
-    if (open_classes_key(HKEY_CLASSES_ROOT, buf, MAXIMUM_ALLOWED, &xhkey))
-    {
-        HeapFree(GetProcessHeap(),0,buf);
-        WARN("couldn't open key for ProgID %s\n", debugstr_w(progid));
-        return CO_E_CLASSSTRING;
-    }
-    HeapFree(GetProcessHeap(),0,buf);
-
-    if (RegQueryValueW(xhkey,NULL,buf2,&buf2len))
-    {
-        RegCloseKey(xhkey);
-        WARN("couldn't query clsid value for ProgID %s\n", debugstr_w(progid));
-        return CO_E_CLASSSTRING;
-    }
-    RegCloseKey(xhkey);
-    return __CLSIDFromString(buf2,clsid);
+    return clsid_from_string_reg(progid, clsid);
 }
 
 /******************************************************************************
diff --git a/dlls/ole32/tests/compobj.c b/dlls/ole32/tests/compobj.c
index 3bc98fcfca9..81f099c30b4 100644
--- a/dlls/ole32/tests/compobj.c
+++ b/dlls/ole32/tests/compobj.c
@@ -368,6 +368,15 @@ static void test_CLSIDFromProgID(void)
     {
         GUID clsid1;
 
+        memset(&clsid, 0xcc, sizeof(clsid));
+        hr = CLSIDFromProgID(wszNonExistent, &clsid);
+        ok(hr == CO_E_CLASSSTRING, "got 0x%08x\n", hr);
+        ok(IsEqualCLSID(&clsid, &CLSID_NULL), "should have zero CLSID on failure\n");
+
+        /* CLSIDFromString() doesn't check activation context */
+        hr = CLSIDFromString(progidW, &clsid);
+        ok(hr == CO_E_CLASSSTRING, "got 0x%08x\n", hr);
+
         clsid = CLSID_NULL;
         hr = CLSIDFromProgID(progidW, &clsid);
 todo_wine