diff --git a/dlls/ole32/compobj.c b/dlls/ole32/compobj.c
index 51e942b041..4a61aca58b 100644
--- a/dlls/ole32/compobj.c
+++ b/dlls/ole32/compobj.c
@@ -1108,6 +1108,43 @@ HRESULT COM_OpenKeyForCLSID(REFCLSID clsid, LPCWSTR keyname, REGSAM access, HKEY
     return S_OK;
 }
 
+/* open HKCR\\AppId\\{string form of appid clsid} key */
+HRESULT COM_OpenKeyForAppIdFromCLSID(REFCLSID clsid, REGSAM access, HKEY *subkey)
+{
+    static const WCHAR szAppId[] = { 'A','p','p','I','d',0 };
+    static const WCHAR szAppIdKey[] = { 'A','p','p','I','d','\\',0 };
+    DWORD res;
+    WCHAR buf[CHARS_IN_GUID];
+    WCHAR keyname[ARRAYSIZE(szAppIdKey) + CHARS_IN_GUID];
+    DWORD size;
+    HKEY hkey;
+    DWORD type;
+    HRESULT hr;
+
+    /* read the AppID value under the class's key */
+    hr = COM_OpenKeyForCLSID(clsid, szAppId, KEY_READ, &hkey);
+    if (FAILED(hr))
+        return hr;
+
+    size = sizeof(buf);
+    res = RegQueryValueExW(hkey, NULL, NULL, &type, (LPBYTE)buf, &size);
+    RegCloseKey(hkey);
+    if (res == ERROR_FILE_NOT_FOUND)
+        return REGDB_E_KEYMISSING;
+    else if (res != ERROR_SUCCESS || type!=REG_SZ)
+        return REGDB_E_READREGDB;
+
+    strcpyW(keyname, szAppIdKey);
+    strcatW(keyname, buf);
+    res = RegOpenKeyExW(HKEY_CLASSES_ROOT, keyname, 0, access, subkey);
+    if (res == ERROR_FILE_NOT_FOUND)
+        return REGDB_E_KEYMISSING;
+    else if (res != ERROR_SUCCESS)
+        return REGDB_E_READREGDB;
+
+    return S_OK;
+}
+
 /******************************************************************************
  *               ProgIDFromCLSID [OLE32.@]
  *
diff --git a/dlls/ole32/compobj_private.h b/dlls/ole32/compobj_private.h
index ac9243caf5..cb4dd64a58 100644
--- a/dlls/ole32/compobj_private.h
+++ b/dlls/ole32/compobj_private.h
@@ -178,6 +178,7 @@ extern void* StdGlobalInterfaceTableInstance;
 extern HRESULT WINE_StringFromCLSID(const CLSID *id,LPSTR idstr);
 
 HRESULT COM_OpenKeyForCLSID(REFCLSID clsid, LPCWSTR keyname, REGSAM access, HKEY *key);
+HRESULT COM_OpenKeyForAppIdFromCLSID(REFCLSID clsid, REGSAM access, HKEY *subkey);
 HRESULT MARSHAL_GetStandardMarshalCF(LPVOID *ppv);
 HRESULT FTMarshalCF_Create(REFIID riid, LPVOID *ppv);
 
diff --git a/dlls/ole32/rpc.c b/dlls/ole32/rpc.c
index 8decc2cbfa..cf55b4ca6e 100644
--- a/dlls/ole32/rpc.c
+++ b/dlls/ole32/rpc.c
@@ -796,9 +796,7 @@ static DWORD start_local_service(LPCWSTR name, DWORD num, LPCWSTR *params)
 static HRESULT create_local_service(REFCLSID rclsid)
 {
     HRESULT hres;
-    WCHAR buf[CHARS_IN_GUID], keyname[50];
-    static const WCHAR szAppId[] = { 'A','p','p','I','d',0 };
-    static const WCHAR szAppIdKey[] = { 'A','p','p','I','d','\\',0 };
+    WCHAR buf[CHARS_IN_GUID];
     static const WCHAR szLocalService[] = { 'L','o','c','a','l','S','e','r','v','i','c','e',0 };
     static const WCHAR szServiceParams[] = {'S','e','r','v','i','c','e','P','a','r','a','m','s',0};
     HKEY hkey;
@@ -807,22 +805,11 @@ static HRESULT create_local_service(REFCLSID rclsid)
 
     TRACE("Attempting to start Local service for %s\n", debugstr_guid(rclsid));
 
-    /* read the AppID value under the class's key */
-    hres = COM_OpenKeyForCLSID(rclsid, szAppId, KEY_READ, &hkey);
+    hres = COM_OpenKeyForAppIdFromCLSID(rclsid, KEY_READ, &hkey);
     if (FAILED(hres))
         return hres;
-    sz = sizeof buf;
-    r = RegQueryValueExW(hkey, NULL, NULL, &type, (LPBYTE)buf, &sz);
-    RegCloseKey(hkey);
-    if (r!=ERROR_SUCCESS || type!=REG_SZ)
-        return hres;
 
     /* read the LocalService and ServiceParameters values from the AppID key */
-    strcpyW(keyname, szAppIdKey);
-    strcatW(keyname, buf);
-    r = RegOpenKeyExW(HKEY_CLASSES_ROOT, keyname, 0, KEY_READ, &hkey);
-    if (r!=ERROR_SUCCESS)
-        return hres;
     sz = sizeof buf;
     r = RegQueryValueExW(hkey, szLocalService, NULL, &type, (LPBYTE)buf, &sz);
     if (r==ERROR_SUCCESS && type==REG_SZ)