diff --git a/pkg/migration/20250624092830.go b/pkg/migration/20250624092830.go
index e17384e29..7477520e4 100644
--- a/pkg/migration/20250624092830.go
+++ b/pkg/migration/20250624092830.go
@@ -27,6 +27,63 @@ func init() {
 		ID:          "20250624092830",
 		Description: "add unique index for task buckets",
 		Migrate: func(tx *xorm.Engine) error {
+
+			s := tx.NewSession()
+			defer s.Close()
+
+			err := s.Begin()
+			if err != nil {
+				return err
+			}
+
+			// First remove all duplicate entries
+			duplicateTaskBuckets := []taskBucket20240406125227{}
+			err = s.
+				Select("task_id, project_view_id").
+				GroupBy("task_id, project_view_id").
+				Having("count(*) > 1").
+				Find(&duplicateTaskBuckets)
+			if err != nil {
+				_ = s.Rollback()
+				return err
+			}
+
+			newTaskBuckets := []taskBucket20240406125227{}
+			for _, bucket := range duplicateTaskBuckets {
+				newBucket := taskBucket20240406125227{}
+				_, err = s.Where("task_id = ? AND project_view_id = ?", bucket.TaskID, bucket.ProjectViewID).
+					Get(&newBucket)
+				if err != nil {
+					_ = s.Rollback()
+					return err
+				}
+
+				newTaskBuckets = append(newTaskBuckets, newBucket)
+			}
+
+			for _, bucket := range duplicateTaskBuckets {
+				_, err = s.Where("task_id = ? AND project_view_id = ?", bucket.TaskID, bucket.ProjectViewID).
+					Delete(&taskBucket20240406125227{})
+				if err != nil {
+					_ = s.Rollback()
+					return err
+				}
+			}
+
+			for _, bucket := range newTaskBuckets {
+				_, err = s.Insert(&bucket)
+				if err != nil {
+					_ = s.Rollback()
+					return err
+				}
+			}
+
+			err = s.Commit()
+			if err != nil {
+				return err
+			}
+
+			// Then create the unique index
 			var query string
 			switch tx.Dialect().URI().DBType {
 			case schemas.MYSQL:
@@ -34,7 +91,7 @@ func init() {
 			default:
 				query = "CREATE UNIQUE INDEX IF NOT EXISTS UQE_task_buckets_task_project_view ON task_buckets (task_id, project_view_id)"
 			}
-			_, err := tx.Exec(query)
+			_, err = tx.Exec(query)
 			return err
 		},
 		Rollback: func(tx *xorm.Engine) error {