Detect whether MS Office installed is 32bit or 64bit by using registry

Question

I want to install vsto addin based on the excel version (32 bit or 64 bit). I am planning to bundle both 32bit and 64 bit msis and install one by determining the excel versi

Answer 1

First, look for the installed version of Outlook in this key:

HKEY_CLASSES_ROOT\Outlook.Application\CurVer

The value will be Outlook.Application.15 (for 2013). Then parse that value to get the integer and lookup this key:

HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Office\15.0\Outlook

If it exists, check the value of Bitness to determine if it is 32-bit (x86) or 64-bit (x64). If it doesn't exist, assume 32-bit.