Users might be unable to sign in to OWA or send emails on Exchange Server
Affected product: Windows Server 2025; Windows Server 2022
Issue reported on Exchange Server 2016, 2019, and Subscription Edition, affecting OWA sign-in and mail delivery.
Technology Updates
Important software changes, known issues, upgrade guidance, security notices and end-of-support milestones relevant to OPCT clients.
Official Microsoft notices
Last checkedMicrosoft Updates & Known Issues
Product notices, issue status and release information from Microsoft.
Remote Desktop connections might fail for non-admin users with error 0xC000000D
Affected product: Windows 11, version 24H2
This issue affects non-admin users connecting through Remote Desktop with Administrator protection enabled.
USB audio devices might fail to start or produce no sound
Affected product: Windows 11, version 26H2; Windows 11, version 25H2; Windows 11, version 24H2; Windows 10, version 22H2; Windows Server 2025
Some USB Audio Class 1.0 devices display Code 10 or fail in multichannel audio modes after installing the Sept. 8 update
Interim guidance for Cuba’s 2026 daylight saving time change
Affected product: Windows announcements
Following an announcement on October 27, 2026, the Republic of Cuba will remain on daylight saving time (UTC-04:00) instead of turning clocks back on November 1, 2026. A Windows up…
Policy-based in-box app removal extended to multi-session environments
Affected product: Windows announcements
If you’re an IT admin, policy-based app removal now supports multi-session environments. Use it to manage the removal of supported in-box apps on devices running Windows 11 Enterpr…
The October 2026 Windows non-security preview update is now available
Affected product: Windows announcements
The October 2026 non-security preview update is now available for Windows 11, versions 26H2, 26H1, and 25H2. Information about the contents of this update is available in the relea…
New MSRC blog: Microsoft’s response to compromised eMudhra certificate authority keys
Affected product: Windows announcements
Microsoft has published a new blog post outlining our response to compromised eMudhra intermediate certificate authority keys, including changes to Windows and Microsoft Edge trust…
Quick machine recovery is now supported on Windows Server 2025
Affected product: Windows announcements
With the October 2026 security update, quick machine recovery extends to Windows Server 2025. Quick machine recovery is designed to help restore devices experiencing widespread boo…
(Updated) Windows updates are available for 2026 time zone changes in Canada
Affected product: Windows announcements
Recent Windows updates add new region-specific time zones for Alberta, British Columbia, and Manitoba. If you use or manage Windows devices in any affected location, install the ap…
Take action: NTLMv1 hardening changes might affect network connections on devices without Credential Guard
Affected product: Windows announcements
Beginning with the October 2026 security update, Windows 11, versions 26H2, 25H2, and 24H2, along with Windows Server 2025, enforce restrictions on generating NTLMv1-derived creden…
Windows Server 2022 has reached end of mainstream support
Affected product: Windows announcements
As of October 13, 2026, Windows Server 2022 has reached end of mainstream support and transitioned to extended support. The October 2026 security update is the last mainstream supp…
90-Day Reminder: Windows Server 2016 will reach end of updates on January 12, 2027
Affected product: Windows announcements
On January 12, 2027, Windows Server 2016 will reach end of updates. The January 2027 Windows security update will be the last update available for this version. After this date, de…
90-Day Reminder: Windows 10 Enterprise LTSC 2021 will reach end of updates on January 12, 2027
Affected product: Windows announcements
On January 12, 2027, Windows 10 Enterprise LTSC 2021 will reach end of updates. The January 2027 Windows security update will be the last update available for this version. After t…
The October 2026 Windows security update is now available
Affected product: Windows announcements
(Updated 10-13-2026 11:30 AM PT: Message updated to reflect availability of Windows 10, versions 22H2 and 21H2.)The October 2026 Windows security update is now available for all su…
Hardening changes for ReFS volumes on removable media
Affected product: Windows announcements
Microsoft is making hardening changes to the Resilient File System (ReFS). The changes improve the security posture of Windows by adding visibility into unsupported external ReFS c…
Windows 11, version 24H2 (Home and Pro) and Windows 10 LTSB 2016 have reached end of updates
Affected product: Windows announcements
Today, October 13, 2026, Windows 11, version 24H2 Home and Pro, and Windows 10 Enterprise LTSB 2016 have reached end of updates. The October 2026 monthly security update is the las…
Manage Administrator protection within Windows 11 security baseline
Affected product: Windows announcements
If your organization uses Windows security baselines, Administrator protection becomes enabled by default with the October 2026 Windows security update. The security baselines for…
AD FS Distributed Key Manager (DKM) container ACL hardening begins today
Affected product: Windows announcements
The October 2026 Windows security update moves AD FS Distributed Key Manager (DKM) container ACL hardening into Enforcement mode. These protections address the elevation of privile…
Microsoft 365 Apps — Version 2610: October 28
Affected product: Microsoft 365 Apps
Read Microsoft’s release notes for the Current Channel desktop apps.
Microsoft 365 Apps — Version 2610: October 21
Affected product: Microsoft 365 Apps
Read Microsoft’s release notes for the Current Channel desktop apps.
Microsoft 365 Apps — Version 2609: October 13
Affected product: Microsoft 365 Apps
Read Microsoft’s release notes for the Current Channel desktop apps.
Microsoft 365 Apps — Version 2609: October 06
Affected product: Microsoft 365 Apps
Read Microsoft’s release notes for the Current Channel desktop apps.
Microsoft 365 Apps — Version 2609: September 30
Affected product: Microsoft 365 Apps
Read Microsoft’s release notes for the Current Channel desktop apps.
Remote Desktop connections might fail for non-admin users with error 0xC000000D
Affected product: Windows 11, version 26H2; Windows 11, version 25H2
This issue affects non-admin users connecting through Remote Desktop with Administrator protection enabled.
USB audio devices might fail to start or produce no sound
Affected product: Windows Server 2022
Some USB Audio Class 1.0 devices display Code 10 or fail in multichannel audio modes after installing the Sept. 8 update
Devices might experience a black screen or desktop loading issues after sign-in
Affected product: Windows 11, version 26H2; Windows 11, version 25H2; Windows 11, version 24H2
Microsoft has received reports of this issue occurring in some virtual desktop environments.
Applications which require AC-3 audio decoding might close unexpectedly
Affected product: Windows 11, version 26H2; Windows 11, version 25H2; Windows 11, version 24H2
This issue is more likely to occur in legacy applications, and unlikely for many modern applications.
Domain-joined devices might lose their secure trust relationship with the domain
Affected product: Windows 11, version 26H2; Windows 11, version 25H2; Windows 11, version 24H2
Some Credential Guard protected machine accounts might be unable to sign in interactively will valid domain credentials.
Incorrect notifications that "Microsoft Defender Antivirus is turned off"
Affected product: Windows 11, version 25H2; Windows 11, version 24H2; Windows 10, version 22H2; Windows Server 2025; Windows Server 2022
Microsoft Defender Antivirus remains active and functioning correctly despite notifications following the latest update.
No notices match these filters.
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