diff --git a/pkg/ddl/ingest/engine.go b/pkg/ddl/ingest/engine.go
index ee214aa469..daf19e4e21 100644
--- a/pkg/ddl/ingest/engine.go
+++ b/pkg/ddl/ingest/engine.go
@@ -54,6 +54,7 @@ type engineInfo struct {
 	openedEngine *backend.OpenedEngine
 
 	uuid        uuid.UUID
+	backend     backend.Backend
 	writerCache generic.SyncMap[int, backend.EngineWriter]
 	memRoot     MemRoot
 	flushLock   *sync.RWMutex
@@ -66,6 +67,7 @@ func newEngineInfo(
 	unique bool,
 	en *backend.OpenedEngine,
 	uuid uuid.UUID,
+	bk backend.Backend,
 	memRoot MemRoot,
 ) *engineInfo {
 	return &engineInfo{
@@ -75,6 +77,7 @@ func newEngineInfo(
 		unique:       unique,
 		openedEngine: en,
 		uuid:         uuid,
+		backend:      bk,
 		writerCache:  generic.NewSyncMap[int, backend.EngineWriter](4),
 		memRoot:      memRoot,
 		flushLock:    &sync.RWMutex{},
@@ -104,26 +107,25 @@ func (ei *engineInfo) Close(cleanup bool) {
 	}
 	err := ei.closeWriters()
 	if err != nil {
-		logutil.Logger(ei.ctx).Error(LitErrCloseWriterErr, zap.Error(err),
+		logutil.Logger(ei.ctx).Warn(LitErrCloseWriterErr, zap.Error(err),
 			zap.Int64("job ID", ei.jobID), zap.Int64("index ID", ei.indexID))
 	}
-
-	indexEngine := ei.openedEngine
-	closedEngine, err := indexEngine.Close(ei.ctx)
+	if cleanup {
+		defer func() {
+			err = ei.backend.CleanupEngine(ei.ctx, ei.uuid)
+			if err != nil {
+				logutil.Logger(ei.ctx).Warn(LitErrCleanEngineErr, zap.Error(err),
+					zap.Int64("job ID", ei.jobID), zap.Int64("index ID", ei.indexID))
+			}
+		}()
+	}
+	_, err = ei.openedEngine.Close(ei.ctx)
 	if err != nil {
-		logutil.Logger(ei.ctx).Error(LitErrCloseEngineErr, zap.Error(err),
+		logutil.Logger(ei.ctx).Warn(LitErrCloseEngineErr, zap.Error(err),
 			zap.Int64("job ID", ei.jobID), zap.Int64("index ID", ei.indexID))
 		return
 	}
 	ei.openedEngine = nil
-	if cleanup {
-		// local intermediate files will be removed.
-		err = closedEngine.Cleanup(ei.ctx)
-		if err != nil {
-			logutil.Logger(ei.ctx).Error(LitErrCleanEngineErr, zap.Error(err),
-				zap.Int64("job ID", ei.jobID), zap.Int64("index ID", ei.indexID))
-		}
-	}
 }
 
 // writerContext is used to keep a lightning local writer for each backfill worker.
diff --git a/pkg/ddl/ingest/engine_mgr.go b/pkg/ddl/ingest/engine_mgr.go
index f53c29d89e..88cf5a49da 100644
--- a/pkg/ddl/ingest/engine_mgr.go
+++ b/pkg/ddl/ingest/engine_mgr.go
@@ -79,6 +79,7 @@ func (bc *litBackendCtx) Register(indexIDs []int64, uniques []bool, tbl table.Ta
 			uniques[i],
 			openedEngine,
 			openedEngine.GetEngineUUID(),
+			bc.backend,
 			bc.memRoot,
 		)
 	}
diff --git a/pkg/lightning/backend/local/engine.go b/pkg/lightning/backend/local/engine.go
index c8c64ea4d5..3a051b608d 100644
--- a/pkg/lightning/backend/local/engine.go
+++ b/pkg/lightning/backend/local/engine.go
@@ -1568,6 +1568,13 @@ type dbSSTIngester struct {
 }
 
 func (i dbSSTIngester) mergeSSTs(metas []*sstMeta, dir string, blockSize int) (*sstMeta, error) {
+	failpoint.InjectCall("beforeMergeSSTs")
+	failpoint.Inject("mockErrInMergeSSTs", func(val failpoint.Value) {
+		if val.(bool) {
+			failpoint.Return(nil, errors.New("mocked error in mergeSSTs"))
+		}
+	})
+
 	if len(metas) == 0 {
 		return nil, errors.New("sst metas is empty")
 	} else if len(metas) == 1 {
diff --git a/tests/realtikvtest/addindextest3/BUILD.bazel b/tests/realtikvtest/addindextest3/BUILD.bazel
index 15e6e98671..d630992643 100644
--- a/tests/realtikvtest/addindextest3/BUILD.bazel
+++ b/tests/realtikvtest/addindextest3/BUILD.bazel
@@ -11,7 +11,7 @@ go_test(
         "temp_index_test.go",
     ],
     flaky = True,
-    shard_count = 37,
+    shard_count = 38,
     deps = [
         "//pkg/config",
         "//pkg/config/kerneltype",
diff --git a/tests/realtikvtest/addindextest3/ingest_test.go b/tests/realtikvtest/addindextest3/ingest_test.go
index 0f50b7d083..0c16d3458d 100644
--- a/tests/realtikvtest/addindextest3/ingest_test.go
+++ b/tests/realtikvtest/addindextest3/ingest_test.go
@@ -17,6 +17,9 @@ package addindextest_test
 import (
 	"context"
 	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -505,6 +508,47 @@ func TestAddIndexAdvanceWatermarkFailed(t *testing.T) {
 	tk.MustGetErrCode("alter table t add unique index idx(b);", errno.ErrDupEntry)
 }
 
+func TestAddIndexTempDirDataRemoved(t *testing.T) {
+	if kerneltype.IsNextGen() {
+		t.Skip("next-gen doesn't use local backend")
+	}
+	tempDir := t.TempDir()
+	defer config.RestoreFunc()()
+	config.UpdateGlobal(func(conf *config.Config) {
+		conf.TempDir = tempDir
+	})
+	store := realtikvtest.CreateMockStoreAndSetup(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+
+	tk.MustExec("create table t (a int);")
+	tk.MustExec("insert into t values (1), (1), (1);")
+
+	testfailpoint.Enable(t, "github.com/pingcap/tidb/pkg/lightning/backend/local/mockErrInMergeSSTs", "1*return(true)")
+	removeOnce := sync.Once{}
+	removed := false
+	testfailpoint.EnableCall(t, "github.com/pingcap/tidb/pkg/lightning/backend/local/beforeMergeSSTs", func() {
+		removeOnce.Do(func() {
+			var filesToRemove []string
+			filepath.WalkDir(tempDir, func(path string, d fs.DirEntry, err error) error {
+				if strings.HasSuffix(path, ".sst") {
+					filesToRemove = append(filesToRemove, path)
+				}
+				return nil
+			})
+			for _, f := range filesToRemove {
+				t.Log("removed " + f)
+				err := os.RemoveAll(f)
+				require.NoError(t, err)
+				removed = true
+			}
+		})
+	})
+
+	tk.MustExec("alter table t add index idx(a);")
+	require.True(t, removed)
+}
+
 func TestAddIndexRemoteDuplicateCheck(t *testing.T) {
 	if kerneltype.IsNextGen() {
 		t.Skip("have overlapped ingest sst, skip")