sdktool cannot find toolchains written by older version

D:\Qt\Opensource\Qt-online\/Tools/QtCreator\bin\sdktool.exe; addKit; --id; qt.54.win32_mingw491_kit; --name; Desktop Qt %{Qt:Version} MinGW 32bit; --toolchain; ProjectExplorer.ToolChain.Mingw:qt.tools.win32_mingw491; --qt; qt.54.win32_mingw491; --debuggerid; Debugger.qt.tools.win32_mingw491; --devicetype; Desktop; UNDOEXECUTE; D:\Qt\Opensource\Qt-online\/Tools/QtCreator\bin\sdktool.exe; rmKit; --id; qt.54.win32_mingw491_kit' failed: Execution failed(Unexpected exit code: 2)

Toolchain ProjectExplorer.ToolChain.Mingw:qt.tools.win32_mingw491 does not exist.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE QtCreatorToolChains>
<!-- Written by sdktool , 2015-06-03T09:31:44. -->
<qtcreator>
 <data>
  <variable>ToolChain.0</variable>
  <valuemap type="QVariantMap">
   <value type="QString" key="ProjectExplorer.GccToolChain.Path">C:\Qt\Qt5.4.2-mingw-enterprise\Tools\mingw491_32\bin\g++.exe</value>
   <valuelist type="QVariantList" key="ProjectExplorer.GccToolChain.SupportedAbis">
    <value type="QString">x86-windows-msys-pe-32bit</value>
   </valuelist>
   <value type="QString" key="ProjectExplorer.GccToolChain.TargetAbi">x86-windows-msys-pe-32bit</value>
   <value type="bool" key="ProjectExplorer.ToolChain.Autodetect">true</value>
   <value type="QString" key="ProjectExplorer.ToolChain.DisplayName">MinGW 4.9.1 32bit</value>
   <value type="QByteArray" key="ProjectExplorer.ToolChain.Id">ProjectExplorer.ToolChain.Mingw:qt.tools.win32_mingw491</value>
  </valuemap>
 </data>
 <data>
  <variable>ToolChain.Count</variable>
  <value type="int">1</value>
 </data>
 <data>
  <variable>Version</variable>
  <value type="int">1</value>
 </data>
</qtcreator>