IDMU tools missing from RSAT installation on Windows 8
IDMU tools is not part of the RSAT installation for Windows 8. There is a documentation error on the support article https://support.microsoft.com/kb/2693643/en-us talks about the presence of IDMU tools under RSAT.
However this has been added back on Windows 8.1 and now IDMU is a part of the RSAT tools for Windows 8.1 released though https://www.microsoft.com/en-us/download/details.aspx?id=39296