Detect whether Office 2010 is 32bit or 64bit via the registry

Question

Now that Office 2010 also comes in a 64bit install, where in the registry do you find out if the version of Office installed is 32bit or 64bit?

Answer 1

From TechNet article on 64-bit editions of Office 2010:

If you have installed Office 2010 including Microsoft Outlook 2010, Outlook sets a registry key named Bitness of type REG_SZ on the computer on which it is installed. The Bitness registry key indicates whether the Outlook 2010 installation is 32-bit or 64-bit. This may be useful to administrators who are interested in auditing computers to determine the installed versions of Office 2010 in their organization.

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

and elsewhere in the same article:

Starting with Office 2010, Outlook is available as a 32-bit application and a 64-bit application. The version (bitness) of Outlook that you choose depends on the edition of the Windows operating system (32-bit or 64-bit) and the edition of Office 2010 (32- or 64-bit) that is installed on the computer, if Office is already installed on that computer.

Factors that determine the feasibility of installing a 32-bit or a 64-bit version of Outlook include the following:

• You can install 32-bit Office 2010 and 32-bit Microsoft Outlook 2010 on a supported 32-bit or 64-bit edition of the Windows operating system. You can install the 64-bit version of Office 2010 and 64-bit Outlook 2010 only on a supported 64-bit operating system.
• The default installation of Office 2010 on a 64-bit edition of the Windows operating system is 32-bit Office 2010.
• The bitness of an installed version of Outlook is always the same as the bitness of Office 2010, if Office is installed on the same computer. That is, a 32-bit version of Outlook 2010 cannot be installed on the same computer on which 64-bit versions of other Office 2010 applications are already installed, such as 64-bit Microsoft Word 2010 or 64-bit Microsoft Excel 2010. Similarly, a 64-bit version of Outlook 2010 cannot be installed on the same computer on which 32-bit versions of other Office applications are already installed.

Answer 2

I've tested Otaku's answer and it appears that the Outlook bitness value is set even when Outlook is not installed, even though the article referenced does not clearly indicate that this would be the case.

Answer 3

I don't have a key called bitness in either of these folders. I do have a key called "default" in both of these folders and the value is "unset" My computer came with office 2010 starter (I assume 64 bit). I removed it and tried to do a full install of 32 bit office. I keep getting the following message. the file is incompatible, check to see whether you need x86 or x64 version of the program.

any advice for me?

Answer 4

You can search the registry for {90140000-0011-0000-0000-0000000FF1CE}. If the bold numbers start with 0 its x86, 1 is x64

For me it was in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\14.0\Registration{90140000-0057-0000-0000-0000000FF1CE}

HTH Clatonh

Answer 5

@clatonh: this is the path of the registry on my PC: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\14.0\Registration{90140000-002A-0000-1000-0000000FF1CE} and it's definitely a 32-bit-installation on a 64-bit OS.