diff --git a/backend/migrations/20251204000002-migrate-recurring-instances.js b/backend/migrations/20251204000002-migrate-recurring-instances.js
index a83ea29..5a78cb6 100644
--- a/backend/migrations/20251204000002-migrate-recurring-instances.js
+++ b/backend/migrations/20251204000002-migrate-recurring-instances.js
@@ -7,65 +7,137 @@ const {
 
 module.exports = {
     async up(queryInterface, Sequelize) {
+        // Check if migration has already been applied by looking for tasks with recurring_parent_id
+        const instanceCount = await queryInterface.sequelize.query(
+            `SELECT COUNT(*) as count FROM tasks WHERE recurring_parent_id IS NOT NULL`,
+            { type: Sequelize.QueryTypes.SELECT }
+        );
+
+        // If no instances exist, migration has likely already run, skip gracefully
+        if (instanceCount[0].count === 0) {
+            console.log(
+                'No recurring instances found, migration may have already run'
+            );
+            await safeRemoveColumn(
+                queryInterface,
+                'tasks',
+                'last_generated_date'
+            );
+            return;
+        }
+
         const templates = await queryInterface.sequelize.query(
             `SELECT * FROM tasks WHERE recurrence_type != 'none' AND recurring_parent_id IS NULL`,
             { type: Sequelize.QueryTypes.SELECT }
         );
 
-        for (const template of templates) {
-            const completedInstances = await queryInterface.sequelize.query(
-                `SELECT * FROM tasks
-                 WHERE recurring_parent_id = :templateId
-                 AND status IN (2, 3)
-                 AND completed_at IS NOT NULL
-                 ORDER BY completed_at ASC`,
-                {
-                    replacements: { templateId: template.id },
-                    type: Sequelize.QueryTypes.SELECT,
-                }
-            );
+        // Disable foreign key constraints for SQLite during deletion
+        const dialect = queryInterface.sequelize.getDialect();
+        if (dialect === 'sqlite') {
+            await queryInterface.sequelize.query('PRAGMA foreign_keys = OFF;');
+        }
 
-            for (const instance of completedInstances) {
-                await queryInterface.bulkInsert('recurring_completions', [
+        try {
+            for (const template of templates) {
+                const completedInstances = await queryInterface.sequelize.query(
+                    `SELECT * FROM tasks
+                     WHERE recurring_parent_id = :templateId
+                     AND status IN (2, 3)
+                     AND completed_at IS NOT NULL
+                     ORDER BY completed_at ASC`,
                     {
-                        task_id: template.id,
-                        completed_at: instance.completed_at,
-                        original_due_date: instance.due_date,
-                        skipped: false,
-                        created_at: instance.completed_at,
-                    },
-                ]);
-            }
-
-            const nextInstance = await queryInterface.sequelize.query(
-                `SELECT * FROM tasks
-                 WHERE recurring_parent_id = :templateId
-                 AND status NOT IN (2, 3)
-                 AND due_date >= date('now')
-                 ORDER BY due_date ASC
-                 LIMIT 1`,
-                {
-                    replacements: { templateId: template.id },
-                    type: Sequelize.QueryTypes.SELECT,
-                }
-            );
-
-            if (nextInstance.length > 0) {
-                await queryInterface.sequelize.query(
-                    `UPDATE tasks SET due_date = :nextDue WHERE id = :templateId`,
-                    {
-                        replacements: {
-                            nextDue: nextInstance[0].due_date,
-                            templateId: template.id,
-                        },
+                        replacements: { templateId: template.id },
+                        type: Sequelize.QueryTypes.SELECT,
                     }
                 );
-            }
 
-            await queryInterface.sequelize.query(
-                `DELETE FROM tasks WHERE recurring_parent_id = :templateId`,
-                { replacements: { templateId: template.id } }
-            );
+                for (const instance of completedInstances) {
+                    // Check if this completion record already exists to avoid duplicates
+                    const existing = await queryInterface.sequelize.query(
+                        `SELECT COUNT(*) as count FROM recurring_completions
+                         WHERE task_id = :taskId
+                         AND completed_at = :completedAt
+                         AND original_due_date = :originalDueDate`,
+                        {
+                            replacements: {
+                                taskId: template.id,
+                                completedAt: instance.completed_at,
+                                originalDueDate: instance.due_date,
+                            },
+                            type: Sequelize.QueryTypes.SELECT,
+                        }
+                    );
+
+                    // Only insert if it doesn't already exist
+                    if (existing[0].count === 0) {
+                        await queryInterface.bulkInsert(
+                            'recurring_completions',
+                            [
+                                {
+                                    task_id: template.id,
+                                    completed_at: instance.completed_at,
+                                    original_due_date: instance.due_date,
+                                    skipped: false,
+                                    created_at: instance.completed_at,
+                                },
+                            ]
+                        );
+                    }
+                }
+
+                const nextInstance = await queryInterface.sequelize.query(
+                    `SELECT * FROM tasks
+                     WHERE recurring_parent_id = :templateId
+                     AND status NOT IN (2, 3)
+                     AND due_date >= date('now')
+                     ORDER BY due_date ASC
+                     LIMIT 1`,
+                    {
+                        replacements: { templateId: template.id },
+                        type: Sequelize.QueryTypes.SELECT,
+                    }
+                );
+
+                if (nextInstance.length > 0) {
+                    await queryInterface.sequelize.query(
+                        `UPDATE tasks SET due_date = :nextDue WHERE id = :templateId`,
+                        {
+                            replacements: {
+                                nextDue: nextInstance[0].due_date,
+                                templateId: template.id,
+                            },
+                        }
+                    );
+                }
+
+                // Delete related records first to avoid foreign key constraints
+                await queryInterface.sequelize.query(
+                    `DELETE FROM tasks_tags WHERE task_id IN (SELECT id FROM tasks WHERE recurring_parent_id = :templateId)`,
+                    { replacements: { templateId: template.id } }
+                );
+
+                await queryInterface.sequelize.query(
+                    `DELETE FROM task_events WHERE task_id IN (SELECT id FROM tasks WHERE recurring_parent_id = :templateId)`,
+                    { replacements: { templateId: template.id } }
+                );
+
+                await queryInterface.sequelize.query(
+                    `DELETE FROM task_attachments WHERE task_id IN (SELECT id FROM tasks WHERE recurring_parent_id = :templateId)`,
+                    { replacements: { templateId: template.id } }
+                );
+
+                await queryInterface.sequelize.query(
+                    `DELETE FROM tasks WHERE recurring_parent_id = :templateId`,
+                    { replacements: { templateId: template.id } }
+                );
+            }
+        } finally {
+            // Re-enable foreign key constraints
+            if (dialect === 'sqlite') {
+                await queryInterface.sequelize.query(
+                    'PRAGMA foreign_keys = ON;'
+                );
+            }
         }
 
         await safeRemoveColumn(queryInterface, 'tasks', 'last_generated_date');