Microsoft addressed a significant bug that affected the launch of Teams and Outlook on ARM-based Windows devices after updates from the August 2026 Patch Tuesday. The issue primarily impacted users of devices like the Surface Pro 11 and Surface Laptop 7 running Windows 11 24H2 or later, who had not installed necessary updates from the Microsoft Store. The bug caused Teams and Outlook to fail to launch or close unexpectedly following the installation of security updates released on or after August 11, 2026 (KB5121003). Classic versions of Outlook and other applications were not affected. A temporary workaround was suggested, involving updating the Auto Super Resolution Package. The bug was resolved through cumulative updates released on September 8, 2026 (KB5124012), and users were urged to install the latest updates for improvements and issue resolutions. Additionally, Microsoft acknowledged other issues related to updates from August, including disruptions in printing and PDF exporting due to .NET Framework updates, gaming problems from peripherals with RGB lighting, and alerts regarding Microsoft Defender Antivirus being disabled. They also fixed issues related to the loss of custom mouse settings and desktop configurations following the installation of the KB5120998 August 2026 preview update.
Microsoft acknowledged an issue with the KB5120998 August 2026 preview update for Windows 11, where mouse settings related to cursor personalization were altered or reset. This problem affected non-English Windows installations, causing personalized settings to fail to load and revert to standard configurations. The issue was resolved in the subsequent KB5124008 September 2026 cumulative update, which users were encouraged to install. KB5120998 was an optional update, potentially limiting the number of affected users. Additionally, Microsoft has been addressing various mouse-related issues in recent months, including problems with the Windows Recovery Environment and disappearing mouse pointers in Outlook.
Microsoft announced that the September 2026 Patch Tuesday updates resolved an issue affecting desktop settings on certain Windows devices, which caused desktop wallpapers to revert to a solid black background after the installation of the KB5120998 August 2026 preview update. This bug impacted Windows 11 24H2 and 25H2 systems, preventing the correct loading of desktop settings and also affecting mouse settings. Microsoft recommended users update their devices to the latest security update released on September 8, 2026 (KB5124008) to benefit from the fix.
Microsoft's Patch Tuesday on September 8, 2026, addressed two critical Windows privilege escalation vulnerabilities: CVE-2026-85880 and CVE-2026-81963, both with a CVSS score of 7.8. CVE-2026-85880 is a heap-based buffer overflow in the Windows Advanced Local Procedure Call (ALPC), allowing attackers with low-privilege local access to escalate privileges to SYSTEM. CVE-2026-81963 involves improper link resolution in the Windows Update Stack, enabling similar privilege escalation. Both vulnerabilities require no user interaction and have been actively exploited prior to the patch release. CISA added them to its Known Exploited Vulnerabilities catalog on September 8, 2026, with a remediation deadline of September 22 for U.S. federal agencies.
CVE-2026-85880 affects various Windows 10 and Server versions but excludes Windows 11 and Windows Server 2025. CVE-2026-81963 impacts newer Windows platforms, including Windows 11 and Windows Server 2025. Microsoft released security updates for both vulnerabilities on September 8, 2026, and organizations are advised to prioritize these updates. Security teams should monitor for signs of privilege escalation and unusual SYSTEM-level activities related to these vulnerabilities.
Microsoft released its September 2026 security updates, addressing two critical Windows elevation-of-privilege vulnerabilities: CVE-2026-85880 and CVE-2026-81963. Both vulnerabilities were exploited before their public disclosure on September 8. CVE-2026-85880 involves a heap-based buffer overflow in the Windows Advanced Local Procedure Call (ALPC), allowing low-privileged attackers to gain SYSTEM privileges. CVE-2026-81963 affects the Windows Update Stack due to improper link resolution and access controls, enabling similar privilege escalation. The September release also includes 974 Common Vulnerabilities and Exposures (CVEs) across various Microsoft products, with 723 affecting Windows. Users of Windows 11 24H2 and 25H2 receive updates via KB5124008, while Windows 11 26H1 receives KB5124012. Windows 11 24H2 Home or Pro editions will reach end of servicing on October 13, 2026. Users are advised to install the updates promptly and back up important data.
Microsoft has acknowledged a software bug causing persistent Windows Security pop-ups that incorrectly indicate antivirus protection is disabled. These notifications began appearing after the latest Microsoft Defender Antivirus updates, but the antivirus is functioning correctly. The issue affects various versions of Windows and Windows Server with the latest Defender updates. Microsoft has committed to resolving the issue in a future update, though no timeline has been provided. Users are advised to verify the status of their antivirus through the Windows Security app and disregard the notifications until a fix is released.
Microsoft is addressing an issue (TM1466820) causing delays or preventing some users from accessing the Microsoft Teams desktop client on Windows systems, acknowledged on Thursday at 16:45 EDT. Affected users may experience loading failures or delays of up to two minutes and are advised to use the web or mobile versions of Teams as a temporary workaround.
Microsoft is analyzing service logs and telemetry data to identify the root cause and has contacted some affected users for more information. Additionally, there is a separate issue (TM1466659) affecting Mac users, preventing them from joining Teams calls and meetings, confirmed on Sunday at 08:32 EDT. Microsoft is reassessing the cause of this disruption.
Earlier this year, Microsoft resolved an issue blocking some Teams Free users from chats and calls. The company also confirmed a bug causing crashes and launch failures for Teams and New Outlook users after recent Windows security updates. Furthermore, there is an ongoing Exchange Online issue affecting multiple mailboxes, resulting in "Server busy" errors and delays in email communications with external domains.
The preview update KB5120998 for Windows 11 versions 24H2 and 25H2, released on August 27, 2026, has caused issues such as erratic mouse pointer behavior and disappearing desktop backgrounds, particularly in non-English versions. Microsoft has acknowledged these problems, indicating that they stem from coding practices that fail to load certain settings correctly. Specific issues include a "black desktop background" due to desktop settings not loading and mouse customization resetting to default configurations. The problems may be related to translation issues within the registry, as registry keys have been altered post-update. Users have suggested that manually adjusting these registry keys could restore normal functionality.
Microsoft has acknowledged a software bug in its Windows operating system that causes misleading pop-up notifications, indicating that antivirus protection is disabled. These alerts began appearing after the latest Microsoft Defender Antivirus updates, despite the antivirus functioning correctly. The notifications can occur at startup and intermittently, and cannot be silenced through standard notification controls. The issue affects various versions of Windows and Windows Server with the latest Defender updates. Microsoft is working on a resolution, but no timeline has been provided. Users are advised to verify their antivirus status through the Windows Security app and can ignore the notifications if real-time protection is confirmed as active.
