Microsoft confirmed its November 2026 security updates are causing Windows activation failures for organisations using automated licensing tools.
The bug blocks new activations and reconfigurations, but machines already activated have up to 180 days of grace. A fix is expected within days, as IT teams juggle multiple November update failures.
This month's Patch Tuesday security updates trigger the 0x80041008 error codes, Microsoft confirmed in a service alert issued on Wednesday, BleepingComputer reported.
"Affected devices might encounter error 0x80041008, Invalid parameter (SWbemObjectEx), when running commands to activate Windows, configure Key Management Service (KMS), or manage product keys", Microsoft said in the alert.
The failures appear after administrators run specific commands for domain setup and product key installation. The issue mainly hits organisations that automate Windows activation and licensing, or run the Software Licensing Management Tool from the command line.
SLMGR is a built-in Windows script IT administrators use from the command line to install product keys and point computers to a licensing server.
KMS, or Key Management Service, is how large organisations activate hundreds of computers internally without each machine contacting Microsoft directly over the internet.
Error 0x80041008 means the system passed an invalid parameter to the Windows management interface, causing the activation script to crash instead of completing.
The affected systems range across several generations, including Windows 10 versions 21H2 and 22H2, Windows 11 version 23H2, and Windows Server editions 2019, 2022 and 2025.
- Windows 10 21H2 and 22H2 Client operating systems affected by the activation failures.
- Windows 11 23H2 The current Windows 11 release experiencing the error.
- Windows Server 2019, 2022 and 2025 Server editions where automated licensing scripts are failing.
Already activated devices are safe
Microsoft reassured customers that devices already activated remain activated. Computers configured with the right keys before the update aren't expected to encounter the problem.
"Devices that are already activated remain activated. Customers whose devices already have the appropriate KMS client key and KMS configuration, and who do not need to run the affected Slmgr.vbs commands, are not expected to be affected", Microsoft said.
For up to 180 days after their last successful check-in, KMS-activated devices stay activated. That means organisations aren't facing an immediate blackout; computers activated before the November patch will keep working for months unless they're newly deployed or reconfigured.
"KMS-activated devices typically remain activated for up to 180 days following successful activation.", Microsoft said.
Customers who don't need to run the affected SLMGR commands aren't expected to be impacted. Organisations needing immediate mitigation are advised to contact Microsoft Support for business.
New activations
Blocked immediately
- Fails with error 0x80041008
- Cannot run SLMGR commands
- Requires Microsoft Support for mitigation
Existing activations
180-day buffer
- Remain activated
- No action needed if configured
- Safe until next check-in window
A month of update failures
The activation bug isn't the only problem IT teams are managing. Microsoft also said the November 2026 Windows 11 security updates will not install on systems that have the October 2026 preview update.
Updates released since the October Patch Tuesday are also triggering SQL Server performance and stability issues. Microsoft faced a similar activation headache in January, when a bug caused license migration failures during upgrades because affected devices couldn't register with the Windows Activation server for digital licenses.
The November 2026 Patch Tuesday was massive, fixing 1,235 flaws including an Outlook zero-day.
Microsoft 365 outage compounds problems
Starting 12 November, a widespread Microsoft 365 outage hit Outlook, Teams, Copilot and Exchange Online, compounding the IT burden. Exchange Online problems started around 11:17 a.m. ET; incident reports placed the wider Microsoft 365 disruption's start at 1:26 p.m. ET.
Some affected servers are back online and stable, Microsoft said, though recovery remains underway. The connectivity problem could affect any region.
A Digital Trends writer speculated that a deluge of AI-written code might be behind these issues, noting Microsoft has not commented on the reasons.
- JanuaryLicense migration bug
Microsoft addressed a known issue causing Windows license migration failures during upgrades.
- October Patch TuesdaySQL Server issues begin
Windows updates released since October trigger SQL Server performance and stability issues.
- 12 NovemberMicrosoft 365 outage
Exchange Online and broader Microsoft 365 services experience a widespread outage.
- November 2026Activation failures
Patch Tuesday updates cause Windows activation and licensing failures with error 0x80041008.
What we know
- The November 2026 Patch Tuesday updates cause Windows activation failures with error 0x80041008.
- Devices already activated remain activated and are not expected to be affected.
- KMS-activated devices typically remain activated for up to 180 days following successful activation.
Still unclear
- When exactly the fix for the 0x80041008 activation error will ship.
- What caused the widespread Microsoft 365 outage that began on 12 November.
- When the Microsoft 365 outage will be fully resolved.
- The root cause of the activation bug and whether it is related to the concurrent SQL Server and installation failures.
Microsoft said a fix for the activation error will be available over the coming days, while recovery from the separate Microsoft 365 outage remains underway.
