Resolving SQL Server Installation Error 0x851A001A: A Comprehensive Guide

Installing SQL Server on modern systems, especially those running Windows 11, can sometimes lead to unexpected errors—particularly when dealing with high-performance storage drives. One of the most frequently encountered issues is the error code 0x851A001A, which appears during the setup process and halts the installation of the SQL Server Database Engine. This error is not a flaw in the software itself but rather a compatibility challenge arising from how modern storage devices report their physical sector sizes to the operating system.

Understanding the Root Cause: Sector Size Incompatibility

At the heart of this issue lies a mismatch between the way certain modern solid-state drives (SSDs) and NVMe devices report their physical sector sizes and what SQL Server expects. While traditional hard drives and older SSDs use a standard 512-byte sector size, newer drives—especially those using advanced technologies like 3D NAND or optimized for performance—may report a physical sector size of 32 KB or more.

SQL Server, however, is designed to work only with 512-byte or 4 KB (4096-byte) physical sector sizes. When the database engine attempts to start during installation, it performs internal consistency checks on the file system. If it detects a sector size larger than 4 KB, it fails to initialize, resulting in the generic error message: "Wait on the Database Engine recovery handle failed". This is the exact symptom associated with error code 0x851A001A.

Diagnosing the Issue: How to Confirm the Problem

Before applying any fix, it's essential to confirm that the root cause is indeed the disk sector size. The setup logs alone may not provide enough detail, so you must dig deeper into the SQL Server error logs.

Step 1: Locate the SQL Server Error Log

After a failed installation, the primary source of diagnostic information is the SQL Server error log. By default, this file is located at:

C:\Program Files\Microsoft SQL Server\MSSQL[version].[InstanceName]\MSSQL\LOG\ERRORLOG

Replace [version] with the actual version number (e.g., 15 for SQL Server 2019) and [InstanceName] with the instance name (e.g., MSSQLSERVER for default instances). Open this file using a text editor like Notepad or Notepad++.

Step 2: Look for Misaligned Read Warnings

Within the error log, search for messages related to "misaligned reads". A key indicator is a line that says:

"256 misaligned reads"

This message confirms that SQL Server detected a mismatch between the expected and actual sector alignment, pointing directly to the underlying sector size issue.

Step 3: Verify the Physical Sector Size of Your Drive

To confirm the drive’s physical sector size, open Command Prompt as an administrator and run the following command, replacing E: with the drive letter where SQL Server is being installed:

fsutil fsinfo sectorinfo E:

In the output, pay close attention to two values:

• PhysicalBytesPerSectorForAtomicity
• PhysicalBytesPerSectorForPerformance

If either of these values exceeds 4096 bytes (e.g., 32768 for 32 KB), then your drive is reporting a non-standard sector size, and this is the root cause of the installation failure.

Applying the Fix: Registry Workaround for Sector Size Emulation

Once confirmed, the solution lies in instructing Windows to emulate a 4 KB sector size for the drive, even if the hardware reports a larger value. This is achieved through a registry modification that forces the storage driver to present a compatible sector size to SQL Server.

Step 1: Access the Registry Editor

Press Win + R, type regedit, and press Enter. Confirm any User Account Control (UAC) prompts.

Step 2: Navigate to the Correct Registry Path

Go to the following key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\stornvme\Parameters\Device

Note: The stornvme key is used for NVMe drives. If you're using a different storage driver (e.g., storport for some SSDs), the path may vary slightly. However, stornvme is the most common for modern NVMe drives.

Step 3: Create the Forced Physical Sector Size Value

Right-click on the Device folder, select New > Multi-String Value, and name it:

ForcedPhysicalSectorSizeInBytes

Double-click the newly created value and enter the following:

* 4095

The * symbol is required and acts as a wildcard to apply the setting to all drives using this driver. The value 4095 forces the system to emulate a 4 KB sector size (since 4096 is the actual 4 KB boundary, 4095 is used as a workaround to trigger emulation).

Step 4: Restart the System

Close the Registry Editor and restart your computer. This step is critical—without a reboot, the registry change will not take effect.

Reinstalling SQL Server Successfully

After the system restarts, attempt the SQL Server installation again. The setup process should now proceed without encountering error 0x851A001A. The Database Engine service will start successfully because Windows is now presenting a compatible 4 KB sector size to SQL Server, even though the underlying hardware uses a larger physical sector.