<p>MySQL Error 1396 ER_CANNOT_USER appears when a CREATE USER, GRANT, or REVOKE statement fails because the referenced account already exists, is undefined, or conflicts with privilege tables.</p>
<p>MySQL Error 1396: ER_CANNOT_USER occurs when a CREATE USER or GRANT command cannot complete due to an existing or mismatched account entry. Ensure the user-host pair is unique or drop the conflicting account to resolve the issue.</p>
Operation %s failed for %s
MySQL raises Error 1396 (SQLSTATE HY000) with the message "Operation %s failed for %s" when a privilege-related statement cannot create, modify, or drop the specified account. The error stops the statement and rolls back any partial changes.
The problem appears most often during CREATE USER, GRANT, REVOKE, ALTER USER, or RENAME USER statements when the account already exists, the host component differs from what is stored, or the privilege tables are corrupted.
The server validates the user@host pair against mysql.user and related tables before executing a privilege statement. Any mismatch, duplicate, or missing entry triggers ER_CANNOT_USER. It is common after host migrations, improper account deletions, or scripted deployments that re-run user creation steps.
Unresolved ER_CANNOT_USER blocks automated provisioning pipelines, prevents new applications from connecting, and leaves security holes when expected privileges are not applied. Clearing the conflict restores predictable and auditable access control.
Duplicate user@host combinations in mysql.user cause the CREATE USER command to fail with ER_CANNOT_USER.
Attempting to GRANT privileges to an account that does not yet exist also triggers the error.
Defining an account with an implicit host value that conflicts with an existing entry leads MySQL to reject the statement.
Corrupted privilege tables or inconsistent replication lag between primary and replicas can surface the error during automated grants.
First, confirm the exact user@host pair involved. Query mysql.user to see if the account already exists or is missing.
If the account exists and you meant to recreate it, DROP USER first or use CREATE OR REPLACE USER in MySQL 8.0.
If the account should not exist, remove the stale row and rerun your CREATE USER or GRANT statement.
Where the account is missing, issue a CREATE USER statement before applying GRANT or REVOKE.
Automated deployments that run CREATE USER on every build often fail the second time. Add IF NOT EXISTS or handle the error gracefully.
Migrating from '%' host to specific hosts can create overlapping accounts. Clean up the wildcard entry before adding new host-specific ones.
Replication lag can cause a GRANT on a replica to fire before the corresponding CREATE USER arrives. Execute all privilege changes only on the primary.
Use idempotent statements like CREATE USER IF NOT EXISTS and ALTER USER for password changes.
Maintain user definitions in version-controlled SQL files and apply them with tools that track state, such as Liquibase or Flyway.
Audit mysql.user regularly for duplicate or orphaned accounts. Remove wildcard hosts that overlap with specific hosts.
Error 1397 (ER_PASSWORD_ANONYMOUS_USER) occurs when a password is set for an anonymous user - remove or rename the anonymous account.
Error 1133 (ER_NONEXISTING_GRANT) fires when you try to revoke privileges from a non-existent account - ensure the user exists first.
Error 1820 (ER_PASSWORD_NO_MATCH) signals that provided passwords do not match - supply identical password strings.
The specified account already exists in mysql.user, so CREATE USER fails.
A GRANT or REVOKE references an account that has not been created yet.
The host portion differs from the stored entry, causing a perceived duplicate.
Manual edits or file corruption make privilege lookups inconsistent.
Raised when a GRANT or REVOKE references a user that does not exist.
Occurs when the two passwords supplied to CREATE USER do not match.
Triggered when trying to set a password for the anonymous user account.
MySQL matches the most specific host first. Query mysql.user to see existing host values, and use SHOW GRANTS FOR 'user'@'host' to verify.
No. You must drop or alter the conflicting account or create the missing one before retrying your privilege statement.
Yes, in MySQL 8.0 it atomically drops and recreates the account, preserving scripts from failing when the user already exists.
Galaxy tracks executed queries, highlights privilege statements, and suggests IF NOT EXISTS or CREATE OR REPLACE snippets via its AI copilot, reducing duplicate account creation.
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