Office 2010 64-bit versus 32-bit install?

We posted earlier about the availability of 64-bit editions of Office 2010. If you are wondering about which edition of Office 2010 to install, the recommendations are as follows:


  • If users in your organization depend on existing extensions to Office, such as ActiveX controls, third-party add-ins, in-house solutions built on previous versions of Office, or 32-bit versions of programs that interface directly with Office, we recommend that you install 32-bit Office 2010 (the default installation) on computers that are running both 32-bit and 64-bit supported Windows operating systems.
  • If some users in your organization are Excel expert users who work with Excel spreadsheets that are larger than 2 gigabytes (GB), they can install the 64-bit edition of Office 2010. In addition, if you have in-house solution developers, we recommend that those developers have access to the 64-bit edition of Office 2010 so that they can test and update your in-house solutions on the 64-bit edition of Office 2010.

Office 2010 provides support for 32-bit Office 2010 applications that run on 64-bit Windows operating systems by using Windows-32-on-Windows-64 (WOW64). WOW64 is the x86 emulator that enables 32-bit Windows-based applications to run seamlessly on 64-bit Windows systems. The 32-bit Office client is supported as a WOW64 installation, which is the default installation on 64-bit Windows operating systems. The 32-bit Windows-based applications run on 64-bit Windows, which allows for compatibility with 32-bit Office applications and add-ins.

To learn about 64-bit Office 2010, see the Microsoft Office 2010 Engineering blog article Understanding 64-Bit Office ( For detailed information about the supported operating systems, supported scenarios, setup process, and deployment considerations for 64-bit Office 2010 clients, see 64-bit editions of Office 2010 ( in the Office 2010 Resource Kit (

For a visual representation of this information, see the 64-bit Client Installation of Microsoft Office 2010 poster (, which includes supported scenarios, deployment considerations, and an overview of the Setup process.

Microsoft is also releasing Microsoft Visual Basic for Applications 7.0 (VBA 7) to work with both 32-bit and 64-bit applications. For more information, see Compatibility Between the 32-bit and 64-bit Versions of Office 2010 ( The article discusses the changes that apply to the 64-bit version of Office 2010 and introduces the new VBA 7 code base.



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