Bitness : How to identify Outlook 2010 installation is a 32-bit or 64-bit?

When Outlook 2010 is installed, it sets the new registry key named Bitness, which indicates whether the Outlook 2010 installation is a 32-bit or 64-bit version. This can be useful to administrators who want to audit computers to determine the installed versions of Outlook 2010 in their organizations.

  • Registry path: HKEY_LOCAL_MACHINE\Software\Microsoft\Office\14.0\Outlook
  • Registry key: Bitness
  • Value: either x86 or x64

For more information about Microsoft Office 2010 in 64-bit, see 64-bit editions of Office 2010.

Comments (4)
  1. In the beta, I find this value only in HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftOffice14.0Outlook.

    Has it changed in later builds?

  2. Deva [MSFT] says:

    Hi Carl,

    Under x64 systems, the registry keys will be available in the path, as you specified:


    Hope this helps.

  3. Thanks for that confirmation Deva. But what's the point of this value on 32-bit systems…

    …which can run only 32-bit Office?

  4. JP says:

    I suppose what you would do is check if HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftOffice14.0Outlook exists (or simply try to read the Bitness value). If it doesn't exist, assume 32-bit.

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