text: ---
  title: "Fatal Error C1852"
  ms.date: "11/04/2016"
  f1_keywords: ["C1852"]
  helpviewer_keywords: ["C1852"]
  ms.assetid: fa011004-b8d6-46f1-ba80-4785e4ce137f
  ---
  # Fatal Error C1852
  
  'filename' is not a valid precompiled header file
  
  The file is not a precompiled header.
  
  ### To fix by checking the following possible causes
  
  1. Invalid file specified with **/Yu** or **#pragma hdrstop**.
  
  1. The compiler assumes a file extension of .pch if you do not specify otherwise.
  