How to fix ERROR 1035: Old key file; repair it in MySQL

Before attempting any repair, export the table using mysqldump to preserve your data:

mysqldump -u root -p database_name table_name > table_backup.sql

This creates a SQL file with the table structure and data that you can restore if the repair fails.

Connect to MySQL and run the REPAIR TABLE command with the QUICK option to try a non-destructive repair:

REPAIR TABLE table_name QUICK;

This tells MySQL to fix the .MYI index file without modifying the .MYD data file. It completes quickly and preserves all your data. Check the output for success or failure.

If the quick repair fails, try the USE_FRM option to rebuild the index file from the table definition file:

REPAIR TABLE table_name USE_FRM;

Warning: This option tells MySQL to ignore the corrupted .MYI header. The AUTO_INCREMENT counter is lost and will be reset. Only use this after QUICK repair fails.

If both previous attempts fail, run a full repair operation (this takes longer):

REPAIR TABLE table_name;

MySQL will perform a complete rebuild of the index file, scanning the data file thoroughly. Monitor disk space during this operation as it may create temporary files.

If the MySQL-based repairs fail, shut down MySQL and repair the table file directly:

# Stop MySQL
sudo systemctl stop mysql

# Quick recovery mode (fast, non-destructive)
myisamchk -r -q /var/lib/mysql/database_name/table_name.MYI

# If quick fails, use safe recovery mode
myisamchk --safe-recover /var/lib/mysql/database_name/table_name.MYI

# Restart MySQL
sudo systemctl start mysql

Replace paths based on your MySQL data directory location.

MySQL provides the mysqlcheck tool to identify and repair multiple tables at once:

# Repair a specific table
mysqlcheck -u root -p --auto-repair database_name table_name

# Repair all tables in a database
mysqlcheck -u root -p --auto-repair database_name

# Repair all tables in all databases
mysqlcheck -u root -p --auto-repair --all-databases

The --auto-repair flag automatically runs REPAIR TABLE if CHECK finds corruption.

If repair attempts fail or report data loss, restore from your backup:

# Stop MySQL
sudo systemctl stop mysql

# Remove or rename corrupted files
sudo mv /var/lib/mysql/database_name/table_name.* /var/lib/mysql/database_name/table_name.corrupt/

# Start MySQL
sudo systemctl start mysql

# Restore from mysqldump backup
mysql -u root -p database_name < table_backup.sql

This completely restores the table from your backup file.