M1 series Macs are without doubt some of the best computers that Apple has ever made, but being the best doesn’t make them ideal for everything. In some cases, they can’t do things that Intel Macs can do very well. One obvious example is Boot Camp, which lets you install and use Windows natively on an Intel Mac. Unless the situation with Microsoft changes in the future, there will never any equivalent to Boot Camp on Apple Silicon Macs. However, if you want to run a native version of Linux outside a virtual machine, Asahi Linux will enable you to do so.

Before you commit yourself to buying or using an M1 series Mac, ensure that your use doesn’t include any of the following. These may seem obvious, but I still get frequent questions from those who are asking the impossible, and hear of new M1 purchasers who are surprised when their new Mac won’t do what they wanted it to.

There are several major differences between Intel and Apple Silicon Macs, of which the most important is that the latter use ARM rather than Intel processors. macOS does include an excellent feature in Rosetta 2 which translates Intel code into ARM so that M1 series Macs can run a great deal which has been built for Intel Macs. However, it has limitations which Apple explains in this article.

What M1 series Macs can’t do

They can’t run any version of macOS before Big Sur, even in a virtual machine, as those are built to run only on Intel processors. Rosetta can’t translate those, nor can virtualisation environments running on M1 Macs run macOS 10.15 or earlier. It seems most unlikely that this will ever be reliable, although in theory an Intel emulator could run them.

They can’t use some app plug-ins that are Intel-only unless the host app is run in Rosetta translation. This is because translation applies to an entire process, including all the code modules which it might load dynamically. The workaround for this is to set the whole app to be run in Rosetta, which allows it to load the Intel-only code, but it won’t then benefit from improvements in ARM performance, and can’t of course load ARM-only code. Plug-ins which run out-of-process using XPC can, though, cross platform.

They can’t run any unsigned native (ARM) code, including command tools. Even your own AppleScript and Automator apps must be signed using at least an ad hoc signature. Note that script-only apps are always run under Rosetta translation, which automatically signs their translated executable code, which allows you to run unsigned Intel code.

They can’t use Intel kernel extensions. This is because Rosetta can’t translate kernel extensions at all. If software relies on a kernel extension, then that must be Universal, and contain full ARM code to perform the functions of that extension.

They can’t run Intel code which relies on some newer Intel instruction sets and processor features, such as AVX, AVX2, and AVX512 vector instructions. Those Intel instructions can’t be translated by Rosetta, but should affect very few apps indeed.

What M1 series Macs don’t do so well

They don’t run any Intel operating systems easily. For Linux, this is unlikely to be a problem as there are some good distros which run natively on ARM, which can then be virtualised well on an M1 Mac. For Windows, this becomes complicated. Windows 10 and 11 for ARM will run well when virtualised, but not all Windows software runs in those ARM versions, and some vendors are very reluctant to let you know whether this would be feasible. It sets up supply chain problems too: if you rely on a Windows app, which in turn relies on Windows 11 for ARM being able to translate and run it, which in turn relies on Parallels Desktop or VMware to virtualise it, then your reliance has multiple points of failure.

Regular Intel versions of Windows can’t run in virtual machines, because normal virtualisation can’t operate across platforms in that way. It is though possible to run Windows 8, for example, in a combined emulator and virtualiser such as UTM or QEMU. This sets up another supply chain problem, and at least for the moment you shouldn’t rely on that all working.

They don’t load third-party Universal kernel extensions as standard. Running an M1 series Mac in Full Security mode prevents the loading and use of all third-party kernel extensions. To enable an M1 series Mac to load and run any third-party kernel extension, you have to set that boot volume to run in Reduced Security using Startup Security Utility in Recovery, then enable the loading of third-party extensions, as Apple explains here.

They handle external bootable disks differently from Intel Macs. Unlike T2 models, booting from an external disk doesn’t require enabling in Startup Security Utility, but each bootable volume requires ownership and LocalSecurity settings. Apple Silicon Macs have to start their boot process from their internal SSD, and can’t start up wholly from an external disk. Although many users have no problems starting them up from external disks, some report that specific models of SSD don’t work reliably.

Because of these, workflows which depend on booting M1 series Macs from external disks can prove troublesome. If you’re used to taking a common external bootable disk between two Macs, for example, you may want to adopt an alternative approach which involves them both starting up from their internal SSDs and accessing common data on the mobile disk instead.

They don’t run everything faster. It’s perfectly possible for good apps to run more slowly on M1 series Macs. The great majority of the software we run today has been developed, refined and tuned for best performance on Intel processors. While many developers are putting effort into improving them on Apple Silicon, they can’t accomplish a decade or more of refinement in just a year or so. The performance we’re enjoying now is just the start; as Apple and developers work more with these new Macs, you should see further improvements, and those apps which currently have bottlenecks should overcome them.

None of these limitations should stop the great majority of Mac users from upgrading successfully to an M1 series Mac. If you’re one of the few who wants to run Nuance dictation software on their Mac, or whose key apps still require a kernel extension which isn’t yet Universal, then a little caution and further checking should offer you the best way ahead.