How to fix Error 5015 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 5015 — “ALTER DATABASE failed. The total size specified must be 1 MB or greater.”

Why This Error Happens

This error occurs when an ALTER DATABASE statement attempts to resize a data or log file (via MODIFY FILE with a SIZE parameter) to a value smaller than the required 1 MB minimum, often due to a miscalculated value passed in KB instead of MB. It can also occur when automated scripts or maintenance jobs reference a stale or incorrect file size variable, or when a file’s FILEGROWTH and SIZE settings conflict after a prior shrink operation. Additionally, corrupted or improperly restored database metadata in sys.master_files can cause SQL Server to misread the current file size, triggering this validation error during the next resize attempt.

Step-by-Step Resolution Guide

Step 1: Review the Exact ALTER DATABASE Statement

  • Open SQL Server Management Studio (SSMS) or Azure Data Studio and locate the exact T-SQL script that triggered the error.
  • Check the SIZE = clause — ensure the value is specified in MB (e.g., SIZE = 50MB, not SIZE = 50KB).
  • Example of a problematic statement:
  ALTER DATABASE SalesDB MODIFY FILE (NAME = SalesDB_log, SIZE = 512KB);
  • Correct it to:
  ALTER DATABASE SalesDB MODIFY FILE (NAME = SalesDB_log, SIZE = 1MB);

Step 2: Check Current File Sizes in sys.master_files

  • Run the following query to inspect current file sizes and growth settings:
  SELECT name, size, growth, is_percent_growth 
  FROM sys.master_files 
  WHERE database_id = DB_ID('SalesDB');
  • Confirm the size column (in 8 KB pages) correctly reflects the actual file size on disk at C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\DATA\.
  • If values appear mismatched or corrupted, note the discrepancy for the next step.

Step 3: Correct the ALTER DATABASE Command with Valid Minimums

  • Re-issue the command ensuring the new size is strictly greater than or equal to 1 MB and greater than the current committed size if growing the file:
  ALTER DATABASE SalesDB 
  MODIFY FILE (NAME = SalesDB_log, SIZE = 5MB, FILEGROWTH = 10%);
  • If resizing a log file after a shrink operation, first run DBCC SQLPERF(LOGSPACE) to confirm actual log usage before setting a new size.

Step 4: Validate Disk Space and File Permissions

  • Confirm the SQL Server service account (e.g., NT Service\MSSQLSERVER) has write permissions on the target data/log directory.
  • Check available disk space on the volume hosting the .mdf/.ldf files using File Explorer or Get-PSDrive in PowerShell.
  • Restart the SQL Server service via Services.msc or net stop MSSQLSERVER && net start MSSQLSERVER if permission changes were made.

Alternative or Verification Steps

  • After applying the corrected ALTER DATABASE statement, re-run SELECT name, size FROM sys.master_files WHERE database_id = DB_ID('SalesDB'); to confirm the new size is reflected and no errors are returned.
  • If the error persists despite correct syntax, restore the database from a known-good backup to a test instance and compare file metadata, as this may indicate underlying corruption in the database’s file structure.