| title | SQL Server 2025 Known Issues |
|---|---|
| description | Known issues, causes, and workarounds for SQL Server 2025 Preview (17.x), covering upgrades, replication, PolyBase, session behavior, platform compatibility (Windows and Linux), backup compression, and other platform-specific limitations. |
| author | MikeRayMSFT |
| ms.author | mikeray |
| ms.reviewer | randolphwest |
| ms.date | 09/16/2025 |
| ms.service | sql |
| ms.subservice | release-landing |
| ms.topic | troubleshooting-known-issue |
| monikerRange | >=sql-server-2016 |
[!INCLUDE sqlserver2025]
This article describes known issues for [!INCLUDE sssql25-md].
[!INCLUDE sssql25-md] has currently identified the following known issues:
- Windows Arm64 not supported
- In-place upgrade fails due to Microsoft Visual C++ Redistributable
- SQL Server on Windows fails to start on machines with more than 64 logical cores per NUMA node
- Database mail on Linux
- SQLPS
- Incorrect behavior of SESSION_CONTEXT in parallel plans
- Access violation exception occurs under certain conditions
- Issue when setting the backup compression algorithm to ZSTD
- Local ONNX models not supported on Linux operating systems
- PBKDF2 hashing algorithm can affect login performance
[!INCLUDE sssql25-md] isn't supported on Windows Arm64. Only Intel and AMD x86-64 CPUs with up to 64 cores per NUMA node are currently supported.
An upgrade from the following versions might fail:
- [!INCLUDE sssql16-md]
- [!INCLUDE sssql17-md]
This can happen when the existing operating system environment is missing the Microsoft Visual C++ Redistributable for Visual Studio 2022, or an older version of this component is installed.
When this happens, the installation log includes an entry like the following example:
This application requires Microsoft Visual C++ Redistributable for
Visual Studio 2022 (x64/x86, version 14.34 at minimum).
Please install the Redistributable, then run this installer again.
For more information, see: https://go.microsoft.com/fwlink/?linkid=2219560.
To complete the upgrade, add or repair the redistributable component, and run the installation again.
To get the redistributable file, review Microsoft Visual C++ Redistributable latest supported downloads.
Issue: SQL Server instances on Windows might fail to start after the installation if the machine has more than 64 logical cores per NUMA node.
For more information, see Limit number of logical cores per NUMA node to 64.
Issue: Database mail on Linux doesn't work when SQL Server is configured to enforce strict encryption.
Currently, the only workaround isn't to enforce strict encryption.
Issue: SQLPS.exe, the SQL Agent PowerShell subsystem, and the SQLPS PowerShell module don't work when SQL is configured to enforce strict encryption.
Currently, the only workaround isn't to enforce strict encryption.
The SQL Server Agent job syspolicy_purge_history reports a failure on step 3. This job runs daily by default. An instance that doesn't enforce strict encryption doesn't reproduce this problem; another option is to disable the job.
Queries that use the built-in SESSION_CONTEXT function might return incorrect results or trigger access violation (AV) dumps when executed in parallel query plans. This issue stems from the way the function interacts with parallel execution threads, particularly when the session is reset for reuse.
For more information, see the Known issues section in SESSION_CONTEXT.
When the Optional parameter plan optimization feature encounters a predicate that is based on a LOB column, an access violation exception can occur. A fix has been identified and will be part of the next preview release of SQL Server 2025.
Large object (LOB) data types in the Database Engine can store data that exceeds 8,000 bytes. These data types store data on a row-overflow data page. A LOB also encompasses data types that store data on dedicated LOB page structures, which use a text or image pointer of in-row references to LOB data pages. For more information about data storage, see Pages and extents architecture guide.
There's a known issue when attempting to set the backup compression algorithm to ZSTD.
When specifying the ZSTD algorithm (backup compression algorithm = 3), the following error message returns:
Msg 15129, Level 16, State 1
Procedure sp_configure '3' is not a valid value for configuration option 'backup compression algorithm'.
Use the new compression algorithm directly in the BACKUP Transact-SQL command instead of setting the server configuration option.
CREATE EXTERNAL MODEL local ONNX models hosted directly on the SQL Server aren't currently available for Linux on [!INCLUDE sssql25-md] RC 1.
In [!INCLUDE sssql25-md], password-based authentication uses PBKDF2 (RFC2898) as the default hashing algorithm. This enhancement improves password security by applying 100,000 iterations of SHA-512 hashing. The increased computational cost of PBKDF2 means slightly longer SQL Authentication login time. This effect is especially noticeable in environments without connection pooling, or where login latency is closely monitored. In pooled environments, the effect is typically minimal.
For more information, see CREATE LOGIN and Support for Iterated and Salted Hash Password Verifiers in SQL Server 2022 CU12.