Sql server 2025 installation error

You are running into a known issue where Windows 11 for some disk drives reports a sector size that SQL Server does not cope with. Microsoft has published an article with workarounds for the problem.

The error indicates that SQL Server 2025 Express is failing to start during setup because the underlying storage reports a disk sector size that SQL Server cannot handle, causing “256 misaligned log IOs” and a fatal termination. This is a known issue on some Windows 10/11 systems and disks.

To proceed, follow these steps:

1. Confirm the misaligned I/O issue in the SQL error log
   1. After the failed installation, open the SQL Server error log for the instance being installed. For SQL Server 2025 Express, it is typically under:
      • C:\Program Files\Microsoft SQL Server\MSSQL17.SQLEXPRESS\MSSQL\LOG\ERRORLOG or
      • C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\LOG\ERRORLOG
   2. Open ERRORLOG in a text editor and verify that it contains a line similar to:

            There have been 256 misaligned log IOs which required falling back to synchronous IO.
      

   3. If this message is present, the failure is due to the disk sector size / misaligned I/O problem described in Microsoft guidance for “There have been 256 misaligned log IOs…”.
2. Apply the disk-sector-size workaround from Microsoft The misaligned I/O error is covered in Microsoft’s article on “Troubleshoot SQL Server errors related to system disk sector size greater than 4 KB.” In this scenario, SQL Server cannot reliably use a drive whose reported logical sector size is larger than 4 KB, so it fails startup during setup. Use the workarounds from that article (for example, moving SQL data/log files to a drive that reports a 4 KB logical sector size, or applying any vendor/firmware/OS updates that change the reported sector size to 4 KB). After applying the recommended workaround for the disk sector size issue, rerun the SQL Server 2025 Express setup.
3. Rerun SQL Server 2025 Express setup
   1. Ensure no pending Windows restart before reinstalling, as recommended in the SQL Server installation guide.
   2. Run the SQL Server 2025 Express installer as an administrator.
   3. During setup, if possible, choose data and log directories on a disk that complies with SQL Server’s I/O requirements (4 KB logical sector size and “guaranteed delivery to stable media”).
4. If installation still fails
   1. Re-check the new ERRORLOG after the retry to confirm whether the misaligned I/O message still appears.
   2. If the misaligned I/O message is gone but the installation still fails with “Wait on the Database Engine recovery handle failed,” review the rest of the error log for a different root cause and address that accordingly.

These steps align with Microsoft’s documented handling of “256 misaligned log IOs” and the generic “Wait on the Database Engine recovery handle failed” installation failures.

References:

• Troubleshoot SQL Server errors related to system disk sector size greater than 4 KB
• SQL Server 2025 known issues
• SQL Server installation guide
• MSSQLSERVER_833
• Error While Installing SQL Server 2022 / 2025 - Microsoft Q&A
• Unable to install SQL server (Setup.exe) Exit code:-2061893606 - Microsoft Q&A