What is new in Windows Server 2025
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Windows Server 2025 known issues and notifications
Find information on known issues and the servicing status for Windows Server 2025. For immediate help with Windows update issues, click here if you are using a Windows device to open the Get Help app or go to support.microsoft.com. Follow @WindowsUpdate on X for Windows release health updates. If you are an IT administrator and want to programmatically get information from this page, use the Windows Updates API in Microsoft Graph.
Current status as of November 6, 2024
Windows Server 2025 is now generally available. It delivers security advancements and new hybrid cloud capabilities in a high performing, AI-capable platform. Windows Server 2025 is Microsoft’s latest Long-Term Servicing Channel (LTSC) release for Windows Server. To download a free 180-day evaluation, visit the Microsoft Evaluation Center.
Windows Server 2025 is offered as an Optional update for Windows Server 2022 and Window Server 2019 devices, if organizations want to do an in-place upgrade. We recommend you use these methods to deploy Windows Server feature updates as Windows Server 2025 is not automatically installed.
To learn more about Windows Server’s Lifecycle Policy, see the Windows Server 2025 lifecycle article.
- Get Windows Server known issues in Graph API
Data is available for supported Windows Server versions
Known issues
See open issues, content updated in the last 30 days, and information on safeguard holds. To find a specific issue, use the search function on your browser (CTRL + F for Microsoft Edge).
| Summary | Originating update | Status | Last updated |
|---|---|---|---|
| Windows Server 2022 and Server 2019 unexpectedly upgraded to Windows Server 2025 This issue has been mitigated. It was observed when updates were managed through some third-party applications. | N/A | Mitigated | 2024-11-13 17:15 PT |
| Windows Server 2025 might not run as expected on devices with high core count This is observed on servers with 256 or more logical processors. Issues may not trigger consistently. | N/A | Resolved KB5046617 | 2024-11-12 10:04 PT |
| Some text might appear in English during the installation process This only occurs when utilizing certain media, such as CD or USB, to install Windows Server 2025 | N/A | Confirmed | 2024-11-01 10:05 PT |
| Error 'boot device inaccessible' might appear in iSCSI environments Servers might see error 'boot device inaccessible' after the installation of Windows Server 2025 | N/A | Confirmed | 2024-11-01 10:05 PT |
Issue details
November 2024
Windows Server 2022 and Server 2019 unexpectedly upgraded to Windows Server 2025
| Status | Originating update | History |
|---|---|---|
| Mitigated | N/A | Last updated: 2024-11-13, 17:15 PT Opened: 2024-11-09, 12:16 PT |
Windows Server 2025 is intended to be offered as an Optional upgrade in Windows Update settings for devices running Windows Server 2019 and Windows Server 2022. Two scenarios were observed in certain environments:
- Some devices upgraded automatically to Windows Server 2025 (KB5044284). This was observed in environments that use third-party products to manage the update of clients and servers. Please verify whether third-party update software in your environment is configured not to deploy feature updates. This scenario has been mitigated.
- An upgrade to Windows Server 2025 was offered via a message in a banner displayed on the device’s Windows Update page, under Settings. This message is intended for organizations that want to execute an in-place upgrade. This scenario has already been resolved.
The Windows Server 2025 feature update was released as an Optional update under the Upgrade Classification: “DeploymentAction=OptionalInstallation”. Feature update metadata must be interpreted as Optional and not Recommended by patch management tools.
We advise organizations to use Microsoft-recommended methods to deploy Windows Server feature updates.
Next steps: Microsoft is working with third-party providers to streamline best practices and recommended procedures. As an interim measure, Microsoft has also temporarily paused the upgrade offer via the Windows Update settings panel. We estimate it will be available in the first half of 2025. All other upgrading methods to install Windows Server 2025 are still available through the usual channels.
Once the offer via Windows Update resumes, IT administrators will be able to control the feature update offer banner by setting the target version to “hold” in the Group Policy “Select the target Feature Update version.” To learn how to manage feature updates via this group policy, see Manage Feature Updates with Group Policy on Windows Server.
Note: The Windows Server 2025 feature update was made available on November 1, 2024, as KB5044284, which was the same KB number used for Windows 11, version 24H2. This is the KB numbering for both client and server Windows updates. Future updates released for Windows Server 2025 and Windows 11, version 24H2 will share the same KB numbers, but will have different release note sites and links.
Affected platforms:
- Client: None
- Server: Windows Server 2025; Windows Server 2022; Windows Server 2019
October 2024
Windows Server 2025 might not run as expected on devices with high core count
| Status | Originating update | History |
|---|---|---|
| Resolved KB5046617 | N/A | Resolved: 2024-11-12, 10:00 PT Opened: 2024-10-31, 13:11 PT |
Servers which have a high number of logical processors might experience issues running Windows Server 2025. This is presently observed on servers which have 256 or more logical processors.
On these devices, one or more of the following issues might be encountered:
- Windows Server 2025 installation or upgrading processes might fail or stop responding.
- Starting or restarting Server might take an excessive amount of time, such as 3 hours or more.
- An error message on a blue screen appears when starting, restarting, or trying to run an application.
Issues may not trigger consistently, for which it is also possible that the server will start and operate without problem.
To determine whether you are encountering this issue because the number of logical processors on the device exceeds 256, open the Windows Task Manager. This can be accomplished by pressing CTRL+SHIFT+ESC. From there, select the Performance tab and note the number of logical processors reported in the bottom half of the window.
Resolution: This issue was resolved by Windows updates released November 12, 2024 (KB5046617), and later. We recommend you install the latest security update for your device as it contains important improvements and issue resolutions, including this one. If you install an update released November 12, 2024 (KB5046617) or later, you do not need to use a workaround for this issue. If you are using an update released before this date, and have this issue, you have the option to apply the following workaround:
To temporarily prevent this issue, you will need to limit the total number of logical processors on the server to 256 or under. Changing the number of logical processors will vary depending on the firmware installed on your device.
To adjust the number of logical processors, follow these steps:
- Restart your server and enter the UEFI Setup. Navigate through the firmware menus, which may vary by manufacturer.
- Locate any option which allows you to adjust the number of cores per socket.
- Set the number of cores per socket to a value that ensures the total number of logical processors is 256 or fewer. Important: The total number of logical processors is calculated by first multiplying the number of sockets by the number of cores per socket, and then multiplying that result by the number of logical processors per core.
- Restart the server.
Affected platforms:
- Client: None
- Server: Windows Server 2025
Some text might appear in English during the installation process
| Status | Originating update | History |
|---|---|---|
| Confirmed | N/A | Last updated: 2024-11-01, 10:05 PT Opened: 2024-10-31, 13:12 PT |
When installing Windows Server 2025, some text might appear in English during the installation process, regardless of the language selected for the installation. This will be noticeable if a language other than English has been selected for installation.
Please note, this only occurs when utilizing media - such as CD and USB flash drives - to install Windows Server 2025. This issue is only present on Windows Server media 25100.1742 and above with the use of Multilanguage User Interface (MUI).
Next steps: We are working on a resolution and will provide more information when it is available.
Affected platforms:
- Client: None
- Server: Windows Server 2025
Error 'boot device inaccessible' might appear in iSCSI environments
| Status | Originating update | History |
|---|---|---|
| Confirmed | N/A | Last updated: 2024-11-01, 10:05 PT Opened: 2024-10-31, 16:09 PT |
Servers which use iSCSI (Internet Small Computer Systems Interface) technology might display an error upon startup, with the message 'boot device inaccessible'.
This is observed on servers operating under NDIS Poll Mode booting from an iSCSI LUN. Under such configuration, the server will experience the error during startup, after the installation of Windows Server 2025 is completed.
Next steps: We are working on a resolution, and it will be available in future Windows monthly update.
Affected platforms:
- Client: None
- Server: Windows Server 2025
Report a problem with Windows updates
To report an issue to Microsoft at any time, use the Feedback Hub app. To learn more, see Send feedback to Microsoft with the Feedback Hub app.
Need help with Windows updates?
Search, browse, or ask a question on the Microsoft Support Community. If you are an IT pro supporting an organization, visit Windows release health on the Microsoft 365 admin center for additional details.
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