Last year, I wrote a long post about using Windows on ARM with Apple silicon Macs, the licensing and support problems with it, and why I felt like it was a bad thing for Microsoft to come out and fully endorse it. If you haven’t read it, it’s here. There are a few relevant points still, but there’s a lot that’s changed as well. In particular since I wrote that, Windows 11 has shipped, as has x64 emulation for Windows 11 on ARM. And WoA in Parallels on Apple silicon has only seemed to become even more popular among consumers…

We always have questions at our licensing boot camps that we do every other month about how to properly license a Mac for Windows. With the increasing popularity of VDI, Windows 365, and Azure Virtual Desktop, that’s also a topic that seems to be on the increase. I’ve been concerned that as Apple Silicon Macs grew in popularity, the answers for properly licensing and running Windows on ARM would continue to be unclear, and that our business customers (Microsoft’s business customers) would gradually see an influx of BYOD users bringing in Apple Silicon Macs, running Windows, in a… questionable licensing state. So I wanted to find some answers.

If you follow me on Twitter, you’ve probably seen me be outspoken about the fact that thus far, from all we could discern based on Microsofts public statements to date:

1. There’s no way to properly license Windows on ARM for use on an Apple silicon Mac.
2. There’s no support when running Windows on ARM on an Apple silicon Mac.

Well, I reached out to Microsoft this week, and the answer to issue 1… appears much more clear. (Issue 2 doesn’t really seem to have changed as much – see that toward the end of this post.)

Based on Microsoft’s initial quotes over a year ago cited in the post linked earlier, about only licensing Windows on ARM with new OEM PCs, I, and seemingly everyone else assumed that was that, and that any ideas anyone had about installing a WIP build of Windows on ARM, or activating that install with a newly purchased Windows retail product key… was up to shenanigans.

For a while, a few people on Twitter pointed out that since the product keys do not differ between x86, x64, and ARM64 releases of Windows 10 (and now Windows 11, sans x86), it would activate – and thus was licensed in their eyes. I’ve pointed out before that just because something activates doesn’t always mean something is properly licensed… (But often, it does.)

A few other people also pointed out – correctly, as it turns out – that the Windows retail (what you’d get if you bought a box or purchased it digitally online) EULA (end user license agreement) does not denote that it’s only for Intel/AMD or x86/x64 releases of Windows. So, there’s nothing constraining it to any one family of hardware (or preventing the use of that retail Windows license or the included product key on ARM64 systems where the OEM didn’t ship Windows on ARM).

To help our customers understand what was and was not correct in terms of licensing Windows on ARM, I recently reached out to Microsoft and asked, specifically, if a user purchased a retail license for Windows 10 or Windows 11, and used that to activate a WIP or other install of Windows 10 on ARM or Windows 11 on ARM, respectively, was it properly licensed? (A single retail license of Windows Pro, for example, can license one physical PC, or one virtual machine – but not both.)

Microsoft’s very helpful and comprehensive response is below:

Yes customers can use retail copies to run Windows 10/11 on Macs, including ARM Macs. The Windows retail EULA does not have any use rights restrictions on the type of device you install Windows on. Note that the EULA does stipulate that not all versions of Windows are supported on all device types, so theoretically customers could run into compatibility issues with performance & support case by case, but this is not a licensing restriction. Customers can find more details on compatibility at https://aka.ms/minhw.

Microsoft response received via email.

I also asked a couple volume-licensing related questions that are a bit nerdy for a blog post, but I will discuss in an upcoming report at work. In a nutshell, Microsoft’s licensing perspective seems to me to be pretty clear, that “a Mac is a Mac”.

So why the hokey title then? Why did I say “it depends?” It comes down to support…

First of all – you still cannot use Boot Camp on an Apple silicon Mac. Apple has intentionally broken it – the utility to configure your Mac and install Windows will not run. This means some applications (and many games) that require Windows running directly on hardware (or hardware that is unavailable within a hypervisor running WoA) are out of the question on Windows on ARM on Apple silicon.

So, secondarily, your options for running Windows on ARM on an Apple silicon Mac are limited to running it in a VM (effectively, Parallels for the time being). But wait…

Finally, note Microsoft’s phrasing above regarding support – just because it’s licensed, doesn’t mean it’s supported. Should a business deploy Windows on ARM on Apple Silicon Macs? I’m not terribly excited about the idea. Note that VMware specifically noted Microsoft’s lack of support for Windows on ARM on Apple silicon Macs as a reason why they do not currently offer VMware Tools, or support, for that configuration for the time being. Currently if you use Parallels on an Apple silicon Mac and something happens, an application doesn’t work, you hit a security issue or something in the OS just stops working… you may well be on your own, potentially without a fix – much like users who install Windows 11 on x64 hardware that doesn’t meet the OS’s strict hardware requirements.

Many of the issues customers are likely to hit on WoA on Apple silicon are likely to be application compatibility issues. Even with x86 and x64 emulation in Windows 11, there is still (and always will be) a range of software, and all Intel-based drivers, that are out of the question. But that’s not unique to WoA running on an Apple silicon Mac… that’s a Windows on ARM thing. And what’s kind of interesting is the increasing popularity of WoA on Apple silicon could help bring some developers around to make their apps (and drivers, etc.) work properly on WoA as a whole, which would be good news for that platform, and could help lift the popularity (and knowledge of) Windows on ARM PCs.

So this is a good news/no news situation. You can license it. But you’re on your own if something happens, and you’ve got a very finite set of options to even do this on your Apple silicon Mac (no Boot Camp, no VMware Fusion).

For businesses, instead of local Windows VMs, I would still recommend looking into VDI (I can’t believe I’m saying this), Windows 365, or Azure Virtual Desktop. You get centralized security and management of Windows, clearly licensed, maintained on a server/service instead of user devices where the guest OS and applications are not likely get patched in any timely manner.