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How will Microsoft Office work on ARM devices?

Windows 11 will work on low-power ARM chip computers, as well as the usual Intel systems.  What does that mean for Microsoft Office?

ARM based devices use less power than Intel chips, so they are more suitable for smaller devices. Microsoft needs to get Windows onto more portable devices and claw back some market-share from Apple and Android.

Intel and ARM chips work very differently. While Windows 11 might look the same on both, under the surface it’s a different story.  Same goes for Microsoft Office.

Since 2017 there’s been a version of Microsoft Office that runs on ARM though not many devices use it.

Microsoft Office desktop apps will work on ARM computers with Windows 11, they say “Office on ARM will feel and perform just like Office on Intel-compatible processors”.  We’ve heard promises like that before and they’ve never been 100% true.

Despite Microsoft’s promises, there are sure to be differences between Intel and ARM based Office. 

ARM with Office plug-ins

In the past, Office compatibility problems are mostly with plug-ins and more complex VBA macros.  That’s applied not just to different CPU architectures but also the move from Intel based 32-bit to 64-bit.

For Windows 11, Microsoft has a new ‘secret sauce’ for ARM, ARM64EC (“Emulation Compatible”).  This new compatibility layer allows a mix of native ARM and Intel based extras to work at the same time. That will be shown in the type of app in Task Manager.

Source: Microsoft

For Office, that means Word, Excel etc will be native ARM programs but any plugins that need Intel x64 options will still work.

“The ARM64EC code in the app will run natively while any x64 code will run using Windows 11 on ARM’s built-in emulation.”

Each program will have to include the ARM64EC module which, of course, Microsoft Office for ARM will.  But instead of doing a full conversion to ARM, developers can gradually move an Intel based program to ARM native.

When and how?

Later in 2021, Windows 11 will be released for ARM based devices.  Microsoft Office for ARM will be available, at least as an option for Microsoft 365 plans.

Yes, we’re being cautious if not a bit cynical about Office on ARM.  That’s because we’ve heard emulation promises from Microsoft too many times before and every time there’s either a list of exceptions or ‘gotchas’ that grows over time.

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