diff --git a/weed/command/filer_copy.go b/weed/command/filer_copy.go
index 5525ebddd4..748a3fcc36 100644
--- a/weed/command/filer_copy.go
+++ b/weed/command/filer_copy.go
@@ -1,12 +1,14 @@
 package command
 
 import (
+	"cmp"
 	"context"
 	"fmt"
 	"io"
 	"net/http"
 	"os"
 	"path/filepath"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -366,6 +368,7 @@ func (worker *FileCopyWorker) uploadFileAsOne(task FileCopyTask, f *os.File) err
 			},
 			&operation.UploadOption{
 				Filename:          fileName,
+				WantMd5:           true,
 				Cipher:            worker.options.cipher,
 				IsInputCompressed: false,
 				MimeType:          mimeType,
@@ -448,6 +451,7 @@ func (worker *FileCopyWorker) uploadFileInChunks(task FileCopyTask, f *os.File,
 				},
 				&operation.UploadOption{
 					Filename:          fileName + "-" + strconv.FormatInt(i+1, 10),
+					WantMd5:           true,
 					Cipher:            worker.options.cipher,
 					IsInputCompressed: false,
 					MimeType:          "",
@@ -476,6 +480,10 @@ func (worker *FileCopyWorker) uploadFileInChunks(task FileCopyTask, f *os.File,
 	for chunk := range chunksChan {
 		chunks = append(chunks, chunk)
 	}
+	// Chunks arrive in completion order, and the ETag hashes them in stored order.
+	slices.SortFunc(chunks, func(a, b *filer_pb.FileChunk) int {
+		return cmp.Compare(a.Offset, b.Offset)
+	})
 
 	if uploadError != nil {
 		var fileIds []string
@@ -580,6 +588,7 @@ func (worker *FileCopyWorker) saveDataAsChunk(reader io.Reader, name string, off
 		},
 		&operation.UploadOption{
 			Filename:          name,
+			WantMd5:           true,
 			Cipher:            worker.options.cipher,
 			IsInputCompressed: false,
 			MimeType:          "",
diff --git a/weed/command/filer_copy_test.go b/weed/command/filer_copy_test.go
new file mode 100644
index 0000000000..01e6e16547
--- /dev/null
+++ b/weed/command/filer_copy_test.go
@@ -0,0 +1,125 @@
+package command
+
+import (
+	"context"
+	"crypto/md5"
+	"crypto/rand"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+
+	"github.com/seaweedfs/seaweedfs/weed/pb"
+	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
+)
+
+type copyTestFiler struct {
+	filer_pb.UnimplementedSeaweedFilerServer
+	volumeHost string
+	nextKey    atomic.Int32
+	mu         sync.Mutex
+	created    *filer_pb.Entry
+}
+
+func (f *copyTestFiler) AssignVolume(ctx context.Context, req *filer_pb.AssignVolumeRequest) (*filer_pb.AssignVolumeResponse, error) {
+	return &filer_pb.AssignVolumeResponse{
+		FileId:   fmt.Sprintf("1,%x637037d6", f.nextKey.Add(1)),
+		Location: &filer_pb.Location{Url: f.volumeHost, PublicUrl: f.volumeHost},
+	}, nil
+}
+
+func (f *copyTestFiler) CreateEntry(ctx context.Context, req *filer_pb.CreateEntryRequest) (*filer_pb.CreateEntryResponse, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	f.created = req.Entry
+	return &filer_pb.CreateEntryResponse{}, nil
+}
+
+func TestUploadFileInChunksStoresChunksInOffsetOrder(t *testing.T) {
+	// The first chunk finishes last, and the server echoes Content-MD5 back
+	// the way a volume server does.
+	volume := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		file, header, err := r.FormFile("file")
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		data, _ := io.ReadAll(file)
+		if strings.HasSuffix(header.Filename, "-1") {
+			time.Sleep(200 * time.Millisecond)
+		}
+		w.Header().Set("Content-MD5", header.Header.Get("Content-MD5"))
+		w.WriteHeader(http.StatusCreated)
+		json.NewEncoder(w).Encode(map[string]any{"name": header.Filename, "size": len(data)})
+	}))
+	defer volume.Close()
+
+	fake := &copyTestFiler{volumeHost: strings.TrimPrefix(volume.URL, "http://")}
+	lis, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	srv := grpc.NewServer()
+	filer_pb.RegisterSeaweedFilerServer(srv, fake)
+	go srv.Serve(lis)
+	defer srv.Stop()
+
+	const chunkSize, chunkCount = 64 * 1024, 3
+	data := make([]byte, chunkSize*chunkCount)
+	rand.Read(data)
+	path := filepath.Join(t.TempDir(), "f.bin")
+	if err := os.WriteFile(path, data, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	f, err := os.Open(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+
+	empty, access, concurrent := "", "url", chunkCount
+	worker := &FileCopyWorker{
+		options: &CopyOptions{
+			replication:        &empty,
+			collection:         &empty,
+			diskType:           &empty,
+			concurrentChunks:   &concurrent,
+			grpcDialOption:     grpc.WithTransportCredentials(insecure.NewCredentials()),
+			volumeServerAccess: &access,
+		},
+		filerAddress: pb.ServerAddress(fmt.Sprintf("127.0.0.1:1.%d", lis.Addr().(*net.TCPAddr).Port)),
+	}
+	task := FileCopyTask{destinationUrlPath: "/dir/", fileSize: int64(len(data)), fileMode: 0o644}
+	if err := worker.uploadFileInChunks(task, f, chunkCount, chunkSize); err != nil {
+		t.Fatal(err)
+	}
+
+	fake.mu.Lock()
+	chunks := fake.created.GetChunks()
+	fake.mu.Unlock()
+	if len(chunks) != chunkCount {
+		t.Fatalf("stored %d chunks, want %d", len(chunks), chunkCount)
+	}
+	for i, c := range chunks {
+		if want := int64(i * chunkSize); c.Offset != want {
+			t.Fatalf("chunk %d is at offset %d, want %d", i, c.Offset, want)
+		}
+		sum := md5.Sum(data[i*chunkSize : (i+1)*chunkSize])
+		if want := base64.StdEncoding.EncodeToString(sum[:]); c.ETag != want {
+			t.Fatalf("chunk %d ETag = %q, want the md5 of its data %q", i, c.ETag, want)
+		}
+	}
+}