--- a/xpcom/glue/standalone/nsXPCOMGlue.cpp
+++ b/xpcom/glue/standalone/nsXPCOMGlue.cpp
@@ -50,17 +50,17 @@ static LibHandleType
 GetLibHandle(pathstr_t aDependentLib)
 {
   LibHandleType libHandle =
     LoadLibraryExW(aDependentLib, nullptr, LOAD_WITH_ALTERED_SEARCH_PATH);
 
 #ifdef DEBUG
   if (!libHandle) {
     DWORD err = GetLastError();
-    LPVOID lpMsgBuf;
+    LPWSTR lpMsgBuf;
     FormatMessageW(
       FORMAT_MESSAGE_ALLOCATE_BUFFER |
       FORMAT_MESSAGE_FROM_SYSTEM |
       FORMAT_MESSAGE_IGNORE_INSERTS,
       nullptr,
       err,
       MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
       (LPWSTR)&lpMsgBuf,