Choose the 32-bit or 64-bit version of Microsoft Office

By default, Microsoft Office 2010 installs the 32-bit version of Office 2010 even if your computer is running 64-bit editions of Windows.

 Note   If you already have a 64-bit version of Office installed on your computer running a 64-bit operating system, the default installation is the 64-bit version of Office.

Office 2010 provides support for the 32-bit version of Office 2010 programs running on 64-bit operating systems by using WOW64, a compatibility environment provided by the operating system that allows a 32-bit application to run on a Windows 64-bit operating system. Using the 32-bit version of Office 2010 allows people to continue to use existing third-party add-ins for Office that are 32-bit.

The 32-bit version of Office 2010 is the recommended option for most users, because it prevents potential compatibility issues with other 32-bit applications, specifically third-party add-ins that are available only for 32-bit operating systems.

• What is in the 32-bit version of Office but is not included in the 64-bit version of Office?

• Compatibility with existing Office files and solutions

• Operating systems required to run 64-bit version of Office

• Install the 64-bit version of Office

What is in the 32-bit version of Office but is not included in the 64-bit version of Office?

• ActiveX controls library, ComCtl   This library contains ActiveX controls that are used to build solutions. It is most commonly used in the following Microsoft Office programs: Access, Excel, and Word.
• SharePoint List control   The list view in SharePoint Technology is not available to people using the 64-bit version of Office.
• 3-D PivotChart views in Excel   Three-dimensional (3-D) PivotChart views in Excel are not available in the 64-bit version of Office. Two-dimensional (2-D) charts are available.

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Compatibility with existing Office files and solutions

 Note   The 64-bit version of Office 2010 is not compatible with any other 32-bit version of Office programs. As a result, you must first uninstall all 32-bit version of Office programs before you install the 64-bit version of Office 2010. The Office 2010 disc includes both 32- and 64-bit versions of Office 2010. To install 64-bit Office 2010, you must run Setup.exe from the x64 folder. For more information, see Install the 64-bit version of Office.

• ActiveX controls library, ComCtl   Any solutions that use these controls do not work. No good alternatives are available for some of these controls.
• Third-party ActiveX controls and add-ins   None of these work with the 64-bit version of Office.

   Note   There is no 64-bit version of Visual Basic 6. As a result, many of these objects need to be ported and rewritten.

• Visual Basic for Applications   The only way that Microsoft Visual Basic for Applications (VBA) that contains the Declare statement work in the 64-bit version of Office is if you update the code manually.
• Compiled Access databases   The .MDE and .ACCDE files, a common way for Access application developers to distribute solutions and protect their intellectually property, do not work in the 64-bit version of Office. You must contact the application vendor to have the vendor recompile, retest, and redistribute the solution in the 64-bit version.
• Messaging Application Programming Interface (MAPI) calls   If you install the 64-bit version of Office, integration with Microsoft Office Communicator is lost, because Communicator is not 64-bit and MAPI calls do not go across the 32-/64-bit boundary. This might also apply to applications that integrate with Microsoft Outlook.

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Operating systems required to run 64-bit version of Office

Your computer must be running at least 64-bit edition Windows Vista or 64-bit edition Windows Server 2008.

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Install the 64-bit version of Office

For people who want to install the 64-bit version Office 2010 programs on a computer that is running either 64-bit editions of Windows Vista or 64-bit editions of Windows Server 2008 operating systems, the following instructions must be followed. In addition, any add-ins you want to run for Office must also be 64-bit editions.

 Important   If you already have a 64-bit version of Office installed on your computer running a 64-bit operating system, running Setup from the root folder installs the 64-bit version of Office.

1. If you were running Office 2010 Setup from the root folder, and you clicked Customize, click Close to exit Setup.
2. When prompted, click Yes to cancel Setup, and then click Close.
3. Go to the x64 folder of the Office 2010 disc, and double-click Setup.exe to run the 64-bit version of Setup.

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