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how to fix physica; sector size when PC has m.2 drives

Peterson Gideon 0 Reputation points
2026-05-12T11:49:12.42+00:00

LargeSectorSizeCheck Checks whether any disk intended for SQL Server data has a physical sector size greater than 4 KB, which is currently unsupported. Warning One or more disks intended for SQL Server data have a physical sector size greater than 4 KB. SQL Server currently supports physical sector sizes up to 4 KB. Review your storage configuration or refer to the documentation for guidance.

SQL Server Database Engine

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  1. Erland Sommarskog 134K Reputation points MVP Volunteer Moderator
    2026-05-12T21:12:04.8966667+00:00

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  3. Q&A Assist
    2026-05-12T11:49:45.41+00:00
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    To fix the LargeSectorSizeCheck warning and allow SQL Server to install or run on a PC with NVMe/M.2 drives that expose a physical sector size greater than 4 KB, adjust the storage configuration so that Windows presents a supported 4-KB sector size to SQL Server.

    SQL Server currently supports only 512-byte and 4,096-byte (4-KB) physical sector sizes for data files. If the NVMe/M.2 drive reports 8 KB, 16 KB, or larger, SQL Server setup raises LargeSectorSizeCheck and the Database Engine may fail to start.

    Use the following steps:

    1. Verify the current sector size
    2. Open an elevated Command Prompt.
    3. Run: 
         fsutil fsinfo sectorinfo <volume path>
      Example for C drive: 
         fsutil fsinfo sectorinfo C:
    4. Check PhysicalBytesPerSectorForAtomicity and PhysicalBytesPerSectorForPerformance. If either is greater than 4096, the drive is currently exposing an unsupported sector size to SQL Server.
    5. Force Windows to emulate a 4-KB physical sector size (modern NVMe/M.2)

    On some newer storage platforms (such as NVMe) that expose a sector size larger than 4 KB, SQL Server requires the ForcedPhysicalSectorSizeInBytes registry key to emulate a 4-KB sector size so that installation and startup succeed.

    High-level steps (per Microsoft guidance):

    1. Add the ForcedPhysicalSectorSizeInBytes registry key under the appropriate storage driver (for example, stornvme). This key forces the OS to emulate a 4-KB sector size for the device.
    2. Reboot the machine for the change to take effect.
    3. After reboot, rerun: 
         fsutil fsinfo sectorinfo <volume path>
      and confirm that the effective physical sector size presented to SQL Server is now 4096 bytes.
    4. Rerun SQL Server setup or restart the SQL Server service.

    Important:

    • Editing the registry is risky. Back up the registry first and follow the documented steps exactly. For detailed registry commands and examples, see the Microsoft article on troubleshooting disk sector size errors.
    • There is no released version of SQL Server that supports physical sector sizes greater than 4 KB. The only supported options are:
      • Use storage that natively exposes 512-byte or 4-KB sectors, or
      • Use the Windows emulation via ForcedPhysicalSectorSizeInBytes so that SQL Server sees 4 KB.
    1. Alternative: move SQL Server data to a supported drive

    If multiple drives exist and only the NVMe/M.2 drive exposes >4 KB sectors:

    1. Identify a drive where fsutil fsinfo sectorinfo shows 512 or 4096 bytes for the physical sector size.
    2. During SQL Server setup (or in an existing instance), configure:
      • Data files (SQLUSERDBDIR / data directory)
      • Log files (SQLUSERDBLOGDIR)
      • tempdb directories to reside on that supported drive.

    If a Storage Spaces pool was created on disks with sector size >4 KB and is used for SQL Server data:

    • Remove the storage pool.
    • Apply one of the supported methods (registry-based emulation or different hardware).
    • Rebuild the storage pool and then install SQL Server on that storage.
    1. Windows 11 and NVMe specifics

    On Windows 11, native NVMe drivers report the actual device sector size (for example, 8 KB or 16 KB) instead of the emulated 4 KB that Windows 10 reported. This can cause SQL Server to see an unsupported sector size even though the same hardware worked on Windows 10.

    Using ForcedPhysicalSectorSizeInBytes is the documented workaround to restore a 4-KB effective sector size for SQL Server on affected Windows 11 systems.

    References:

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