You sit down to start work on your new Snapdragon-powered laptop, try to open Teams – and it shuts down. You open Outlook – and it crashes too. This isn’t a hardware failure, nor have you done anything wrong. If you are facing issues where Teams and Outlook won’t open on Windows 11 (specifically the 26H1 ARM version), rest assured: this is an officially confirmed bug caused by Microsoft’s own August 2026 security update. The good news is that a solution is now available. In this troubleshooting guide, we’ll cover the details – what happened, who is affected, and how to fix it step-by-step.
Where did this issue come from? Here’s the full picture.
This bug was triggered by Windows security updates (KB5121003) released on or after August 11, 2026, causing apps to either fail to launch or close unexpectedly.
For users running Windows 11 26H1, this issue is linked to the KB5121000 update.
Following the installation of Windows security updates (KB5121000) on or after August 11, 2026, Microsoft Teams and the new Outlook for Windows may fail to launch on ARM-based devices such as the Surface Pro 11 and Surface Laptop 7.
Classic versions of Outlook, Word, and Excel are not affected by this issue.
In short – if you use the older Classic Outlook, it will continue to work fine. The problem affects only the new Outlook and Microsoft Teams – and specifically on ARM-based Windows PCs.
First, check this: Is your PC actually ARM-based?
This issue affects only devices with ARM processors. Since the problem is specific to ARM-based PCs, first verify whether your PC is ARM-based – check the “System type” in the device specifications. If it has an ARM-based processor, proceed; if it has an x64-based processor, then this specific known issue is not the reason why Teams or Outlook are failing to open.
How to check your System Type:
- Click Start → Open Settings.
- Go to System → About.
- Check “System type” in the “Device specifications” section.
- If it says “ARM-based processor” – then this guide is for you.
- If it says “x64-based processor” – then the issue with Teams/Outlook is due to another reason.
Step 2 – Check your Windows version and updates
The documented affected platforms are: Windows 11, version 26H1; Windows 11, version 25H2; and Windows 11, version 24H2. Only client devices are affected; no server platforms are listed.
Check the Windows version:
- Press Win + R → type winver → press Enter.
- The pop-up that appears will show your Windows version and OS Build number.
- If the version is 26H1 and the build number is 26100.9168 or later, you may be affected.
Check Installed Updates:
- Go to Settings → Windows Update → Update history.
- Check whether KB5121000 (for 26H1) is installed.
- If this update is installed and Teams/Outlook have not been opening since then, this is the cause.
Official Fix – Microsoft’s Official Workaround
Microsoft has officially provided a workaround: Update the Auto Super Resolution Package to version 1.0.19.0 or later via the Microsoft Store.
The workaround provided by Microsoft is to open the Microsoft Store, select Downloads → Check for updates, and then install the latest update for the Auto Super Resolution Package (version 1.0.19.0 or later).
Step-by-step method:
Step 1 – Open the Microsoft Store:
- Click the Microsoft Store icon on the taskbar, or search for “Microsoft Store” in the Start Menu.
Step 2 – Go to the Updates section:
- Click on “Library” at the bottom left within the Microsoft Store.
- You will see a “Get updates” or “Check for updates” button at the top right – click on it.
Step 3 – Find the Auto Super Resolution package:
- Find the “Auto Super Resolution Package” in the list of updates.
- If an update is available, click the “Update” button.
- This package must be version 1.0.19.0 or higher.
Step 4 – Allow the update to complete:
- Wait for the update to install.
- After that, reopen both Microsoft Teams and Outlook and check.
Microsoft has not publicly explained why this package technically resolves application-launch failures, but it is an officially recommended and confirmed workaround.
Install Permanent Fix – September 2026 Update
This issue has been resolved by a Windows update (KB5124012) released on September 8, 2026.
This bug has been resolved in the September 2026 Patch Tuesday cumulative updates. Users can address this issue by installing update KB5124012, which was released on September 8, 2026.
How to install KB5124012:
Method #1 – From Windows Update:
- Open Settings → Windows Update.
- Click on “Check for updates”.
- You will see KB5124012 or the September 2026 cumulative update – download and install it.
- Allow the PC to restart.
Method #2 – From the Microsoft Update Catalog:
If it does not appear in Windows Update, you can download it directly.
🔗 catalog.update.microsoft.com
Type KB5124012 in the search bar, download the correct update for your OS version, and install it.
If Teams/Outlook still won’t open after the update, try these steps.
In some cases, the issue may persist even after the update is installed. That is when these additional troubleshooting steps come in handy:
Step 1 – Repair or Reset Microsoft Teams:
- Open Settings → Apps → Installed apps.
- Find Microsoft Teams → Click on the three dots → Advanced options.
- Try “Repair” first – if that doesn’t work, try “Reset”.
- Note: Resetting will clear the local Teams data, but your account and chats will remain safe on the cloud.
Step 2 – Repair New Outlook:
- Same method – Settings → Apps → Outlook (new) → Advanced options → Repair/Reset.
Step 3 – Repair the Microsoft Store:
- Press Win + X → Open Windows PowerShell (Admin).
- Run this command:
wsreset.exe- The Microsoft Store cache will be cleared and the Store will restart – check for updates again.
Step 4 – Reinstall Teams and Outlook:
If Repair/Reset does not work:
- Settings → Apps → Microsoft Teams → Uninstall.
- Open Microsoft Store → Search for “Microsoft Teams” → Install.
- Repeat the same process for Outlook as well.
Step 5 – Check for errors in Event Viewer:
- Win + X → Open Event Viewer.
- Go to Windows Logs → Application.
- Look for entries related to Teams or Outlook – checking the error details can reveal the exact cause.
Use Classic Outlook – Temporary Solution
Classic Outlook and web apps are still working.
If you need immediate access to your emails and the new Outlook is crashing, these alternatives will help:
Classic Outlook (if installed):
- Search for “Outlook (classic)” in the Start Menu.
- If you have a Microsoft 365 subscription, it might be installed on your PC.
Outlook Web App:
🔗 outlook.live.com or outlook.office.com (For Office 365 users)
Teams Web App:
🔗 teams.microsoft.com
- Open this link in your browser – the web version of Teams runs on ARM PCs without any issues.
Teams Mobile App:
Install the Microsoft Teams app on Android or iOS and join meetings from your phone.
Which devices are most affected by this issue?
The ARM-related Outlook and Teams failure also affects Windows 11 26H1, which relies on specific silicon such as Qualcomm’s Snapdragon X2.
This issue affects users of ARM-based hardware running Windows 11 24H2 or later, including the Surface Pro 11 and Surface Laptop 7.
Microsoft noted that this problem is most likely to occur on new or freshly imaged PCs that have not yet installed Microsoft Store updates.
In India, this issue can be observed on laptops powered by Snapdragon X Elite and X Plus processors, such as the Samsung Galaxy Book4 Edge, ASUS Vivobook S 15, Dell XPS 13 9345, Lenovo ThinkPad T14s Gen 6, and HP OmniBook X.
What is Microsoft’s status on this issue?
The dashboard status is “Mitigated,” meaning Microsoft has published a measure to address the immediate problem. This is not a fully integrated Windows fix; Microsoft states that it will deliver a resolution in a future Windows update.
This problem is yet another in a long series of issues linked to the August Patch Tuesday update.
The good news is that the KB5124012 update from September 8, 2026, has officially resolved this issue – so the easiest and most reliable solution is to keep your Windows updated to the latest version.
Free tools that will help with troubleshooting.
1. Windows Update Troubleshooter – Free (Built-in)
Settings → System → Troubleshoot → Other troubleshooters → Windows Update → Run
It automatically detects and fixes update-related issues.
2. Microsoft Support and Recovery Assistant (SaRA) – Free
🔗 aka.ms/SaRA-Download
Microsoft’s official tool that automatically diagnoses problems with Teams and Outlook.
3. PC Health Check Tool – Free
🔗 microsoft.com/en-us/windows/windows-11#pchealthcheck
This tool checks Windows compatibility and the update status of your PC.
4. Event Viewer – Free (Built-in)
Win + X → Event Viewer → Windows Logs → Application
You can find the Teams or Outlook crash logs here, which reveal the exact error code.
5. Microsoft Store Cache Reset (wsreset.exe) – Free (Built-in)
Running the wsreset.exe command in PowerShell (Admin) clears the Store cache and allows the Auto Super Resolution Package update to install correctly.
If Teams and Outlook still fail to open on your ARM Windows PC, or if you encounter repeated errors while installing Windows updates even after trying all the steps mentioned above, visit fixtech.in. They offer professional services for resolving Windows ARM compatibility issues and troubleshooting software problems.
Quick Summary – The entire problem and solution in one place.
| Problem | Teams and new Outlook crash or fail to launch on ARM PC |
| Cause | August 2026 update KB5121000 (26H1) / KB5121003 (24H2, 25H2) |
| Affected Devices | Surface Pro 11, Surface Laptop 7, Snapdragon X PCs |
| Workaround | Auto Super Resolution Package v1.0.19.0+ update from the Microsoft Store |
| Permanent Fix | KB5124012 update (September 8, 2026) |
| Not Affected | Classic Outlook, Word, Excel, x64-based PCs |
FAQs – Teams and Outlook not opening on Windows 11 26H1 ARM
Q1. Is this issue limited to Surface devices?
Microsoft cited the Surface Pro 11 and Surface Laptop 7 as examples, not as an exhaustive list of affected devices. This means any Snapdragon ARM PC could be affected.
Q2. Can I use Classic Outlook instead?
Classic Outlook, Word, Excel, and other applications are unaffected by this issue. Until the new Outlook is fixed, you can use Classic Outlook or the web version.
Q3. What is the Auto Super Resolution Package?
The Auto Super Resolution Package supports AI-enhanced gameplay on Copilot+ PCs. It does not appear to be directly connected to Teams or Outlook, but Microsoft has officially recommended updating it as a workaround.
Q4. Will updating via the Microsoft Store result in data loss?
No. The Auto Super Resolution Package is merely a system component. Updating it does not affect personal data, Teams chats, or Outlook emails.
Q5. Is a PC restart required after installing the September 8 update?
Yes. Restarting the PC is necessary after installing KB5124012. Once restarted, both Teams and Outlook function normally.
Q6. Is this issue occurring only in India?
No, it is affecting ARM Windows users globally – the problem has been reported in the USA, UK, and Europe. Snapdragon laptop users in India are also affected.
Q7. Can I roll back Windows to an older version?
Yes, it is technically possible; you can remove KB5121000 by going to Settings → Windows Update → Update history → Uninstall updates. However, this is not recommended as it also removes security patches. It is better to install the September update.
Q8. What if I don’t have a Microsoft 365 subscription?
Both the free version of Teams and Outlook.com accounts work in web browsers. Use the browser version until a permanent fix is installed.
Final Thoughts
Teams and Outlook failing to open on Windows 11 26H1 ARM is a frustrating situation – especially when you’ve purchased a premium Snapdragon laptop only to have your work stalled right from day one. The good news, however, is that the problem has been identified, an official workaround is available, and a permanent fix was released on September 8, 2026. Start by updating the Auto Super Resolution Package from the Microsoft Store, then install KB5124012; if the issue persists, seek professional assistance at fixtech.in. Ultimately, the failure of Teams and Outlook to launch on Windows 11 26H1 ARM is a fixable problem – it simply requires following the correct steps.