For people using a Surface Pro 11, Surface Laptop 7, or another Windows on Arm machine, the immediate consequence can be severe despite the limited stated scope. Teams and Outlook are often core work applications. A PC that signs in successfully but cannot open either app can become impractical for meetings, mail, and day-to-day collaboration. Yet the official advisory also supplies an important qualifier: the issue is most likely on new or freshly imaged machines that have not yet received Microsoft Store updates.
That distinction changes the response. This is primarily a case for checking the Store update state before considering disruptive measures such as removing a security update.
What Microsoft has confirmed
The affected scenario is tied to Windows security updates released on or after August 11, including KB5121003. Microsoft identifies Microsoft Teams and the new Outlook for Windows as the affected applications on Arm-based devices. The documented symptoms are failure to launch or unexpected closure after launch.
Microsoft names the Surface Pro 11 and Surface Laptop 7 as examples, not as an exhaustive device list. The release-health entry applies to Windows 11 versions 24H2, 25H2, and 26H1. No Windows Server platform is listed for this issue.
The dashboard status is Mitigated, meaning Microsoft has published a measure intended to address the immediate problem. That is not the same thing as a fully integrated Windows correction. Microsoft also says it is working on a resolution to be delivered in a future Windows update, without giving a date or update number.
The known-issue notice followed earlier reports from a small number of users who described Teams and new Outlook failures on Arm64 systems after KB5121003. Those reports helped establish that the behavior was not isolated, but they should not be mistaken for a measure of its prevalence. Neither the official notice nor the available independent reporting establishes how many PCs, organizations, or hardware configurations are affected.
The apps affected — and the ones Microsoft does not list
The wording around Outlook is especially important. Microsoft specifies the new Outlook for Windows, rather than Outlook generally. It says classic Outlook is not known to be affected. Word, Excel, and other applications are likewise not known to be affected.
That provides a useful troubleshooting boundary. If classic Outlook launches normally while the new Outlook does not, that pattern fits the published issue more closely. If Teams, new Outlook, Word, Excel, and unrelated desktop software all fail, the published advisory alone is not enough to explain the broader failure. A different system, account, installation, or connectivity issue could be involved.
It also means IT departments should avoid messages that tell every Outlook user on Windows on Arm to expect an outage. The supplied evidence supports a narrower conclusion: two specific modern Microsoft apps can fail on some Arm-based Windows 11 systems after the named update period, with newly provisioned PCs lacking Store updates identified as the likeliest exposure group.
Why a gaming package appears in an Office-app workaround
Microsoft’s prescribed mitigation is to open Microsoft Store, go to Downloads, select Check for updates, and install Auto Super Resolution Package version 1.0.19.0 or later.
Auto Super Resolution, or Auto SR, is a Windows feature associated with games. It allows supported games to render at a lower resolution and then upscale the result, with the aim of delivering more detailed visuals and smoother frame rates. Microsoft lists the current Auto SR package as a requirement for supported Snapdragon and AMD Ryzen platforms.
That makes the workaround counterintuitive: a component described publicly in gaming terms appears in the resolution path for collaboration and mail applications. But it would be a mistake to turn that surprising link into a declared technical explanation.
Microsoft has not publicly disclosed the root cause of the Teams and new Outlook failures in the material available here. It has not said that Auto SR itself is defective, that it directly causes the app crashes, or that a particular app-packaging or compatibility subsystem is responsible. The safest reading is simply that the package version is part of Microsoft’s mitigation path. Users and administrators should apply the stated update without assuming they have identified the underlying fault.
A practical recovery sequence for affected Arm PCs
For an Arm-based PC where Teams or the new Outlook will not start after recent Windows updates, the least disruptive sequence follows Microsoft’s stated guidance:
- Open the Microsoft Store.
- Go to Downloads.
- Choose Check for updates.
- Install the Auto Super Resolution Package if version 1.0.19.0 or a newer release is offered.
- Try Teams and the new Outlook again after the Store updates have completed.
This is particularly relevant during device setup, after a reset, or following an enterprise reimage. Windows Update and Microsoft Store updates are separate servicing paths, and Microsoft specifically points to systems that have not yet installed Store updates as the most likely affected group. Completing the usual Store update pass should therefore be part of a new Arm PC provisioning checklist, not merely an optional post-setup task.
Organizations may need to assess that advice against their own Store-management policies. The published material does not establish whether every managed environment will receive the necessary Store package immediately, especially where Store access or automatic Store updates are restricted. In such environments, help desks should verify package availability and version state rather than assume that a user can self-remediate.
Some early user accounts said removing the update restored app function. That observation is not Microsoft’s recommended remedy and does not show that uninstalling the security update is suitable for all systems. Security updates serve an important protective purpose, and the official workaround is the Store package update. Removing a security update should not be treated as the standard response to this incident.
A separate update regression affects mouse settings
The Teams and new Outlook issue arrived alongside a different Windows 11 known issue that can be easy to conflate with it. The second issue concerns mouse personalization rather than Arm app launches.
After Windows updates released on or after August 27, 2026, including KB5120998 and later, some mouse personalization settings can revert to their standard values. Microsoft includes custom cursors and cursor animations among the settings that may be affected.
This problem has a different scope and condition. Microsoft attributes it to code components used in non-English Windows installations. On impacted locales, the relevant settings fail to load. More frustratingly, manually putting the preferred cursor or animation settings back does not succeed while the issue remains active.
The documented affected versions are Windows 11 24H2 and 25H2. Version 26H1 is not listed for the mouse-customization regression. Conversely, 26H1 is listed for the Teams and new Outlook launch issue. The difference is a useful reminder not to treat a shared month of updates as evidence of one shared defect.
For users affected by the cursor problem, repeated attempts to restore the same personalization options are unlikely to resolve it while the known issue persists. Microsoft says it is working on a future Windows-update resolution, but has not announced when that update will arrive.
Why Windows 11 26H1 needs separate treatment
Windows 11 26H1 appears in the app-launch advisory, but it should not be viewed as an ordinary feature update that existing 24H2 or 25H2 installations will simply receive in place. Microsoft describes 26H1 as a targeted release for select new devices, not a version designed for in-place installation on existing 24H2 or 25H2 PCs.
The first 26H1 devices launched with Qualcomm Snapdragon X2 Series processors. In practical terms, that means a support organization should not use the 26H1 entry in the affected-version list to imply that every current Windows 11 Arm PC can move to 26H1 as a remedy. The Store-package mitigation, rather than a feature-version transition, is the documented immediate action.
What this incident says about Arm PC readiness
The incident does not establish that Windows on Arm is broadly unreliable, and it does not show that KB5121003 universally prevents Teams and new Outlook from running. Microsoft’s own language is conditional, with exposure concentrated most heavily on newly set-up or freshly imaged PCs missing Store updates.
Still, it highlights a concrete operational reality for Arm deployments: a usable Windows installation depends on more than a completed Windows Update scan. Store-delivered components can be material to the functionality of major applications, even where the relationship is not obvious to the user.
For individuals, the lesson is straightforward: after setting up an Arm PC, run Windows Update and check Microsoft Store updates before relying on it for a meeting or mailbox migration. For IT teams, the stronger lesson is procedural. Build Store-update validation into provisioning, test the exact Teams and new Outlook workflows on the image used for new devices, and keep classic Outlook availability in mind where it remains appropriate to an organization’s setup.
Microsoft’s mitigated status gives affected users a defined next step, but it does not close every question. The technical cause has not been published, the affected population is not quantified, and the final Windows-based correction is still pending. Until that arrives, accurate triage matters: update the Store package first, avoid overstating the scope, and treat the separate non-English cursor regression as its own issue with its own version boundaries.