Why copying to system32 automatically copies to sysWOW64 instead?

I'm trying to copy a file to C:\windows\system32 by calling CopyFileA - debugging shows that indeed the string "C:\windo开发者_C百科ws\system32\filename" is sent to CopyFileA, but my file is copied to "C:\windows\system32\sysWOW64\filename" instead. Does anyone know why does that happen?

On 64bit Windows, Windows does filesystem redirection for 32bit processes. To disable, call Wow64DisableWow64FsRedirection

For the app to also run on 32bit Windows XP, Wow64DisableWow64FsRedirection must be dynamically linked at run-time. Here is the code I use:

BOOL DisableWow64FsRedirection(PVOID* OldValue)
{
#ifdef WIN64
    UNREFERENCED_PARAMETER(OldValue);
    return TRUE;
#else
    typedef BOOL (WINAPI * LPWOW64DISABLEWOW64FSREDIRECTION)(PVOID *);

    LPWOW64DISABLEWOW64FSREDIRECTION    fnWow64DisableWow64FsRedirection;
    HMODULE                             kernelMod;
    BOOL                                success = TRUE;

    kernelMod = GetModuleHandleW(L"kernel32");
    if (kernelMod)
    {
        fnWow64DisableWow64FsRedirection = (LPWOW64DISABLEWOW64FSREDIRECTION)GetProcAddress(kernelMod, "Wow64DisableWow64FsRedirection");
        if (fnWow64DisableWow64FsRedirection)
            success = fnWow64DisableWow64FsRedirection(OldValue);
    }

    return success;
#endif
}

BOOL RevertWow64FsRedirection(PVOID OldValue)
{
#ifdef WIN64
    UNREFERENCED_PARAMETER(OldValue);
    return TRUE;
#else
    typedef BOOL (WINAPI * LPWOW64REVERTWOW64FSREDIRECTION)(PVOID);

    LPWOW64REVERTWOW64FSREDIRECTION fnWow64RevertWow64FsRedirection;
    HMODULE                         kernelMod;
    BOOL                            success = TRUE;

    kernelMod = GetModuleHandleW(L"kernel32");
    if (kernelMod)
    {
        fnWow64RevertWow64FsRedirection = (LPWOW64REVERTWOW64FSREDIRECTION)GetProcAddress(kernelMod, "Wow64RevertWow64FsRedirection");
        if (fnWow64RevertWow64FsRedirection)
            success = fnWow64RevertWow64FsRedirection(OldValue);
    }

    return success;
#endif
}

Simply if you want to check the operating system then check it and access the folder system32 is like:

string os = Environment.GetEnvironmentVariable("WINDIR") + "\\SysWOW64";
            if (Directory.Exists(os))
            {
                destinationDir = Path.Combine(Environment.ExpandEnvironmentVariables("%windir%"), "sysnative\\");
        }

By this you can copy the file in system32 folder.

Enjoy: Ali Raza

this solution seems better for me: credit to Bevan Collins.

BOOL changeWow64Redirection(PVOID& param, BOOL toDisable = true)
{
#ifdef WIN64
  UNREFERENCED_PARAMETER(OldValue);
  return TRUE;
#else
  typedef BOOL (WINAPI * LPWOW64CHANGEWOW64FSREDIRECTION)(PVOID *);
  LPWOW64CHANGEWOW64FSREDIRECTION     fnWow64ChangeWow64FsRedirection;
  HMODULE                             kernelMod;
  BOOL                                success = FALSE;
  kernelMod = GetModuleHandle(_T("kernel32"));
  if (kernelMod)
  {
    if (toDisable)
      fnWow64ChangeWow64FsRedirection = (LPWOW64CHANGEWOW64FSREDIRECTION)GetProcAddress(kernelMod, "Wow64DisableWow64FsRedirection");
    else
      fnWow64ChangeWow64FsRedirection = (LPWOW64CHANGEWOW64FSREDIRECTION)GetProcAddress(kernelMod, "Wow64RevertWow64FsRedirection");
    if (fnWow64ChangeWow64FsRedirection)
      success = fnWow64ChangeWow64FsRedirection(&param);
  }
  return success;
#endif //WIN64
}