function IsFileInUse(fName : string) : boolean; var HFileRes : HFILE; begin Result := false; if not FileExists(fName) then exit; HFileRes := CreateFile(pchar(fName), GENERIC_READ or GENERIC_WRITE, 0 {this is the trick!}, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); Result := (HFileRes = INVALID_HANDLE_VALUE); if not Result then CloseHandle(HFileRes); end;