Microsoft Teams and New Outlook Launch Failures on ARM-based Windows PCs After Recent Updates

According to a report from BleepingComputer published on September 3, 2026, Microsoft is working to fix a known issue that causes crashes and launch failures for Microsoft Teams and New Outlook users on ARM-based Windows PCs. The problems began appearing after installing updates released since the August 2026 Patch Tuesday. Affected users report that both applications fail to start or crash shortly after launch. Microsoft has acknowledged the issue but has not disclosed the root cause or provided a specific timeline for a fix. The company classified the issue as an operational reliability problem rather than a security vulnerability, and there is no evidence of active exploitation in the wild. The report notes that the impact is primarily productivity-focused, leaving users of ARM-based Windows devices unable to use the affected Microsoft 365 applications. No CVEs or security advisories have been associated with the issue to date.