diff --git a/server/src/db/connection.ts b/server/src/db/connection.ts
index 40b2e16..b820a79 100644
--- a/server/src/db/connection.ts
+++ b/server/src/db/connection.ts
@@ -112,6 +112,44 @@ const runMigrations = () => {
     db.exec('PRAGMA foreign_keys = ON');
     userTableInfo2 = db.prepare("PRAGMA table_info(users)").all() as { name: string }[];
   }
+
+  // Fix any tables with stale FK references to users_old (SQLite quirk after table rename)
+  const tablesWithBrokenFK = db.prepare(`
+    SELECT name, sql FROM sqlite_master 
+    WHERE type='table' AND sql LIKE '%users_old%'
+  `).all() as { name: string; sql: string }[];
+  
+  if (tablesWithBrokenFK.length > 0) {
+    console.log('Fixing stale FK references to users_old...');
+    db.exec('PRAGMA foreign_keys = OFF');
+    db.exec('BEGIN');
+    
+    for (const table of tablesWithBrokenFK) {
+      const fixedSql = table.sql.replace(/["']?users_old["']?/g, 'users');
+      const tempName = `${table.name}_fk_fix`;
+      
+      // Get column names
+      const columns = db.prepare(`PRAGMA table_info(${table.name})`).all() as { name: string }[];
+      const columnList = columns.map(c => c.name).join(', ');
+      
+      // Recreate table with fixed FK
+      db.exec(fixedSql.replace(`CREATE TABLE ${table.name}`, `CREATE TABLE ${tempName}`));
+      db.exec(`INSERT INTO ${tempName} SELECT ${columnList} FROM ${table.name}`);
+      db.exec(`DROP TABLE ${table.name}`);
+      db.exec(`ALTER TABLE ${tempName} RENAME TO ${table.name}`);
+      
+      console.log(`  Fixed FK in table: ${table.name}`);
+    }
+    
+    // Recreate indexes for affected tables
+    db.exec('CREATE INDEX IF NOT EXISTS idx_quizzes_user ON quizzes(user_id)');
+    db.exec('CREATE UNIQUE INDEX IF NOT EXISTS idx_quizzes_share_token ON quizzes(share_token)');
+    db.exec('CREATE INDEX IF NOT EXISTS idx_payments_user ON payments(user_id)');
+    
+    db.exec('COMMIT');
+    db.exec('PRAGMA foreign_keys = ON');
+  }
+
   if (didDropApiKeyColumns) {
     logOnce(
       'migration.users_drop_api_keys',