Defensive Security & Blue Team BleepingComputer 1 month ago

Microsoft Teams, Outlook fail to launch on ARM-based Windows PCs

CN
CyberNew Threat Research Desk
• Original Reporting: BleepingComputer
CyberNew Threat Intel Assessment
Assessed Severity: MEDIUM
Impacted Surface
Client Endpoints & Operating Systems
Intelligence Sector
Defensive Security & Blue Team

Analyst Takeaway

"Microsoft is working to fix a known issue that causes crashes and launch failures for Microsoft Teams and New Outlook users after installing updates released since the August 2026 Patch Tuesday. These issues affect only ARM-based Windows devices like the Surface Laptop 7 and Surface Pro 11 that run Windows 11 24H2 or later, and they mainly impact users who haven't installed Microsoft Store..."

Recommended Defense & Mitigation

  • Threat Monitoring: Ingest published IOCs into SIEM/EDR detection rules for continuous telemetry monitoring.
  • Security Awareness: Alert staff and maintain baseline endpoint hardening across endpoints.
Curated & Verified by CyberNew Threat Intelligence Desk Standard Defense Framework (NIST / MITRE ATT&CK)

Windows

Microsoft is working to fix a known issue that causes crashes and launch failures for Microsoft Teams and New Outlook users after installing updates released since the August 2026 Patch Tuesday.

These issues affect only ARM-based Windows devices like the Surface Laptop 7 and Surface Pro 11 that run Windows 11 24H2 or later, and they mainly impact users who haven't installed Microsoft Store updates yet.

"After installing Windows security updates released on or after August 11, 2026, (KB5121003), Microsoft Teams and the new Outlook for Windows might fail to launch or might close unexpectedly on ARM-based devices, such as Surface Pro 11 and Surface Laptop 7," Microsoft said in a Windows release health update.

"Classic Outlook, Word, Excel, and other applications are not known to be affected. This issue is most likely to occur on new or freshly imaged PCs that have not yet installed any Microsoft Store updates."

While Microsoft didn't share the root cause, it advised affected customers to update the Auto Super Resolution Package, which the company says allows "Copilot+ PCs to use AI to make supported games play more smoothly with enhanced details."

Although Microsoft did not disclose the root cause, it advised affected customers to update the Auto Super Resolution Package as a temporary workaround. According to Microsoft, this package enables Copilot+ PCs to use AI to make gameplay smoother.

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Source Verification & Original Intelligence

This threat report was reviewed by CyberNew analysts and cross-referenced with primary security disclosures from BleepingComputer.

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