For the first time, Microsoft Office will come in both 32-bit and 64-bit flavours. Having just been released to manufacturing, Office 2010 will be the first version of Office able to address the full 64-bit memory space, and you will have to make the decision whether to deploy Office 2010 64-bit or 32-bit. Today I will examine some considerations regarding the installation of Office 2010 64-bit and 32-bit. In my next post I will discuss the advantages and disadvantages of Office 2010 64-bit.

Office 2010 32-bit

With the ever-increasing availability of high-storage RAM, 64-bit processors and the systems to power them, all at prices within the reach of every consumer and SOE, 64-bit computing is fast becoming the normal state of play.

According to the Microsoft 2010 Engineering blog, customers who have access to download the product media (such as customers with a VL agreement with Software Assurance, and MSDN/TechNet subscribers) will have a choice about which version they would like to download (both are available). Customers who buy the physical media will receive both versions. Software Assurance customers will have access to the media from April 27th.

Installing Office 2010 64-bit on Windows 7 64-bit

Although Windows XP came in a 64-bit flavour, Windows Vista was the first Microsoft OS to make it especially accessible and feasible for everyday computing. There was comprehensive driver support (eventually) and very few compatibility or stability issues. Windows 7 64-bit has proven to be very popular in both consumer and business environments, and Microsoft has been working hard to ensure that it’s full product suite accommodates both platforms.

If you are running a 64-bit version of Windows deciding on which version to install will depend completely on how you use Microsoft Office. Obviously only the 32-bit version can be installed on a 32-bit version of Windows, but there should not be the automatic assumption that if you’re running a 64-bit version of Windows, that the 64-bit version of Office is the logical choice.

Office 2010 64-bit is supported on 64-bit editions of Windows Vista SP1, Windows 7, Windows Server 2008 SP1 and Windows Server 2008 R2. It is not supported on Windows XP x64. Office 2010 server products such as SharePoint Server, SharePoint Foundation and Project Server are supported on the 64-bit version of Windows Server 2008 SP2 and Windows Server 2008 R2.

Installing Office 2010 32-bit on Windows 7 64-bit

The 32-bit version of Office will run fine on 64-bit Windows, as do most 32-bit applications thanks to the x86 emulator WOW64 which runs on all 64-bit versions of the operating system. Because the operating system can reference the 64-bit memory address space and can therefore make use of physical RAM above 4GB, the 32-bit version of Office will automatically receive a performance boost when running on 64-bit Windows, due to reduced memory swapping, disk read/writes and disk thrashing in a multi-application environment. This is the scenario which Microsoft envisages will be the most appropriate for the vast majority of users.

Installing Office 2010 64-bit and 32-bit on the same computer

The two versions of Office 2010 cannot exist side-by-side on the same physical system. This is true whether a single Office product is installed or the full suite. For example, if the Office installer finds Outlook 2010 x86 installed, it won’t allow you to install Word 2010 x64, so the 32-bit version would have to be removed fully before the 64-bit version could be installed.

Additionally, if you have any of the following 32-bit applications installed, an installation of Office 2010 64-bit will be blocked:

  • Microsoft Excel 2010 Viewer
  • Access database engine of Microsoft Access 2010
  • Microsoft Office 2010 (Click-to-run)
  • Compatibility Pack for Office 2007

Although a reason for this has not yet been fully articulated, it makes sense that the supporting Office infrastructure and shared programs must all be on the same platform. It is also possible that the different versions might be usable on the same physical system if one of them has been virtualized, using Microsoft Application Virtualization for example. The latest build, version 4.6, supports 64-bit apps and 64-bit operating systems.

Office 2010 Upgrade Paths

If you’re already running Office 2007, you can upgrade to Office 2010 32-bit on either a 32-bit or 64-bit version of Windows. Office 2007 cannot be upgraded from 32-bit to Office 2010 64-bit (this is a limitation which is consistent across all Microsoft products). There is no information currently available as to whether it is possible to upgrade from Office 2003 to Office 2010.

  1. Andreas Erson 13 years ago

    “If you’re already running Office 2007, can you upgrade to Office 2010 32-bit on either a 32-bit or 64-bit version of Windows.”

    Switch places on “can” and “you”.

  2. Thanks!

  3. Dave 13 years ago

    Note that Windows Mobile Device Center does not support Outlook x64. In fact it DELETES all contacts/calender items on the mobile device. MS have no plans to fix?!?

  4. do wash 13 years ago

    I’m running 32-bit Office 2010 on 64-bit Windows 7. My programs run fine, my system accepts all 64-bit program updates but will not install updates for Office 2010. Each time I shut Windows 7 down it tries to load the Office 2010 updates unsuccessfully. This occurs everytime I turn the computer off. Do I have upgrade to the 64-bit version of Office 2010?

  5. Author
    James Bannan 13 years ago

    You shouldn’t have to run a 64-bit version of Office – the 32-bit version works just fine.

    I’d have a look through the application logs in the event viewer and see why those updates aren’t installing. Try installing some manually and see whether that helps.

  6. Paul 12 years ago

    Thank you for this clarity. I appreciate the time you took to explain this; I’m a techie, but having the conciseness is appreciated and incredibly useful. All of my 32-bit macros in Excel are broken with my migration to a new machine running Win7 64-bit; I purchased the 64-bit office not knowing the problems I would have in backward compatibility. I’m uninstalling Office Pro 2010 64 and will fight for a 32-bit license.



  7. Dhooghe 11 years ago

    Have PC with Win 7 64 bit installed. Have installed office 2010 as 32 bit, but would like to migrate to Office 64 bit. I do not have a large number of Excel or Word documents to worry about, but I use Outlook.
    What would happen to Outlook in the migration from 32 to 64 bit? My Contacts in Outlook are very important and, if lost, would be problematic.
    Can I back up the Contacts and e-mail and then import into Outlook Office 64 bit? I’m not a technical wiz, therefore, if I try anything it has to be in small manageable steps.
    Would Power Point from Office 64 bit accept PP presentations made in Office PP 32 bit?
    I sometimes have PP Presentations of 800-900Mb. These include many high resolution photographs. I hope that the 64 bit may help with these large files.
    Best regards,

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