Preparing for Office 2010 64-bit

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Installing 64-bit Office 2010 is all in the preparation …

If you have a 64-bit edition of Windows and want to use Office 2010 64-bit then before installing you need to make some decisions and do some preparation.

64-bit Office software is definitely faster than the default 32-bit software but anyone wanting that speed has to make sure there’ll be no compatibility issues.

Operating System

64-bit Office 2010 will only run on the 64-bit editions of Windows 7 or Vista as well as 64-bit Windows Server 2003 or 2008. If there’s anyone out there with 64-bit Windows XP they’ll have to upgrade.

32-bit Office 2010 will run on Windows 7, Vista, 2003/2008 Server editions as well as the 32-bit edition of Windows XP.

Windows Mobile

Windows Mobile Device Center is the software from Microsoft that connects Outlook to a Windows Mobile device.  Microsoft has decided to NOT support Outlook 64-bit links to Windows Mobile devices.

Microsoft managed to keep this quiet and you can understand why because it’s incredibly emabarassing for the company and a major reason for people to choose a non-Microsoft mobile device. has a separate article on this astonishing and deliberate failure by Microsoft.


If you rely on any third-party add-ins, DLL’s etc then you need to get specific 64-bit versions. Check with the developer – if they don’t have them yet they are probably in the works.

Even if the add-in comes from Microsoft and is specifically for Office 2010 does NOT mean it will be 64-bit compatible.  The Outlook Social Connector is currently only available for 32-bit versions of Office, including the Office 2010 beta.


According to Microsoft ‘most’ existing VBA code will run unchanged in 64-bit Office but this is the same company that’s being very cautious about encouraging deployment of the same software. Talk about having a bet both ways.

The major issues for VBA code are:

Linked binaries. These have to be 64-bit versions. Office 2010 64-bit can’t work with 32-bit binaries.

This includes the common controls ofMSComCtl(TabStrip, Toolbar, StatusBar, ProgressBar, TreeView, ListViews, ImageList, Slider, ImageComboBox) and the controls ofMSComCt2(Animation, UpDown, MonthView, DateTimePicker, FlatScrollBar).

And also

64-bit Office 2010 does not provide 64-bit versions of the Common Controls.

Having controls from Microsoft is no guarantee either since the company has not fully ported their own controls to 64-bit.

We’ve seen suggestions, but no hard data, to suggest that Office 2010 64-bit will have problems working with Sharepoint sites where there are ActiveX controls required.

For developers there’s plenty of information here and a link to a Compatibility Inspector which will check code for 64-bit readiness..

Pointers and handles returned from 64-bit Office will be shortened when stored in a 32-bit variable space. Any such variables need to be converted to 64-bit length but, even better, there is now a specific pointer data type in VBA 7. In other words, instead of use ‘Long’ as a data type for pointers, use ‘LongPtr’.

There is a new ‘PtrSafe’ option as in ‘Declare PtrSafe Function …’ which tells the compiler that the function is 64-bit OK.

Admittedly for non-developers this is all so much phlogiston. Suffice to say that if you use anything but basic VBA code or any add-ins – then you should check before installing 64-bit Office 2010.

Sadly, not even Microsoft itself has ported all the necessary components to 64-bit so sticking with the ‘Microsoft advantage’ is no assurance.


There is no migration option available from 32-bit Office to 64-bit.  You have to uninstall all 32-bit components first and start from scratch.

That means any configuration you have on your Office software is lost and you’ll have to reset Office 2010 as you like it after install.  Make sure you make a note of any setting details before uninstalling Office 32-bit.





If possible, install 64-bit Office 2010 on a trial basis before committing to it. This will also let you decide whether there are any speed/performance benefits that balance any compatibility problems.

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