diff --git a/cmd/slackdump/internal/diag/redownload.go b/cmd/slackdump/internal/diag/redownload.go
new file mode 100644
index 00000000..56ebd4df
--- /dev/null
+++ b/cmd/slackdump/internal/diag/redownload.go
@@ -0,0 +1,189 @@
+package diag
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"os"
+	"path/filepath"
+
+	"github.com/rusq/fsadapter"
+	"github.com/rusq/slack"
+
+	"github.com/rusq/slackdump/v3/cmd/slackdump/internal/bootstrap"
+	"github.com/rusq/slackdump/v3/cmd/slackdump/internal/cfg"
+	"github.com/rusq/slackdump/v3/cmd/slackdump/internal/golang/base"
+	"github.com/rusq/slackdump/v3/internal/chunk"
+	"github.com/rusq/slackdump/v3/internal/chunk/transform/fileproc"
+	"github.com/rusq/slackdump/v3/internal/structures"
+	"github.com/rusq/slackdump/v3/processor"
+)
+
+var cmdRedownload = &base.Command{
+	UsageLine: "tools redownload [flags] <archive_dir>",
+	Short:     "attempts to redownload missing files from the archive",
+	Long: `# File redownload tool
+Redownload tool scans the directory with Slackdump Archive, validating the files.
+If a file is missing or has zero length, it will be redownloaded from the Slack API.
+The tool will not overwrite existing files, so it is safe to run multiple times.
+
+Please note:
+
+1. It requires you to have a valid authentication in the selected workspace.
+2. Ensure that you have selected the correct workspace using "slackdump workspace select".
+3. It only works with Slackdump Archive directories, Slack exports and dumps
+are not supported.`,
+	FlagMask:    cfg.OmitAll &^ cfg.OmitAuthFlags,
+	Run:         runRedownload,
+	PrintFlags:  true,
+	RequireAuth: true,
+}
+
+func runRedownload(ctx context.Context, _ *base.Command, args []string) error {
+	if len(args) != 1 {
+		base.SetExitStatus(base.SInvalidParameters)
+		return errors.New("expected exactly one argument")
+	}
+	dir := args[0]
+	if fi, err := os.Stat(dir); err != nil {
+		base.SetExitStatus(base.SUserError)
+		return fmt.Errorf("error accessing the directory: %w", err)
+	} else if !fi.IsDir() {
+		base.SetExitStatus(base.SUserError)
+		return errors.New("expected a directory")
+	}
+	if fi, err := os.Stat(filepath.Join(dir, "workspace.json.gz")); err != nil {
+		base.SetExitStatus(base.SUserError)
+		return fmt.Errorf("error accessing the workspace file: %w", err)
+	} else if fi.IsDir() {
+		base.SetExitStatus(base.SUserError)
+		return errors.New("this does not look like an archive directory")
+	}
+
+	if n, err := redownload(ctx, dir); err != nil {
+		base.SetExitStatus(base.SApplicationError)
+		return err
+	} else {
+		if n == 0 {
+			slog.Info("no missing files found")
+		} else {
+			slog.Info("redownloaded missing files", "num_files", n)
+		}
+	}
+
+	return nil
+}
+
+func redownload(ctx context.Context, dir string) (int, error) {
+	cd, err := chunk.OpenDir(dir)
+	if err != nil {
+		return 0, fmt.Errorf("error opening directory: %w", err)
+	}
+	defer cd.Close()
+
+	channels, err := cd.Channels()
+	if err != nil {
+		return 0, fmt.Errorf("error reading channels: %w", err)
+	}
+	if len(channels) == 0 {
+		return 0, errors.New("no channels found")
+	}
+	slog.Info("directory opened", "num_channels", len(channels))
+
+	sess, err := bootstrap.SlackdumpSession(ctx)
+	if err != nil {
+		return 0, fmt.Errorf("error creating slackdump session: %w", err)
+	}
+	dl, stop := fileproc.NewDownloader(
+		ctx,
+		true,
+		sess.Client(),
+		fsadapter.NewDirectory(cd.Name()),
+		cfg.Log,
+	)
+	defer stop()
+	// we are using the same file subprocessor as the mattermost export.
+	fproc := fileproc.NewExport(fileproc.STmattermost, dl)
+
+	total := 0
+	for _, ch := range channels {
+		if n, err := redlChannel(ctx, fproc, cd, &ch); err != nil {
+			return total, err
+		} else {
+			total += n
+		}
+	}
+
+	return total, nil
+}
+
+func redlChannel(ctx context.Context, fp processor.Filer, cd *chunk.Directory, ch *slack.Channel) (int, error) {
+	slog.Info("processing channel", "channel", ch.ID)
+	f, err := cd.Open(chunk.FileID(ch.ID))
+	if err != nil {
+		return 0, fmt.Errorf("error reading messages: %w", err)
+	}
+	defer f.Close()
+	msgs, err := f.AllMessages(ch.ID)
+	if err != nil {
+		return 0, fmt.Errorf("error reading messages: %w", err)
+	}
+	if len(msgs) == 0 {
+		return 0, nil
+	}
+	slog.Info("scanning messages", "num_messages", len(msgs))
+	return scanMsgs(ctx, fp, cd, f, ch, msgs)
+}
+
+func scanMsgs(ctx context.Context, fp processor.Filer, cd *chunk.Directory, f *chunk.File, ch *slack.Channel, msgs []slack.Message) (int, error) {
+	lg := slog.With("channel", ch.ID)
+	total := 0
+	for _, m := range msgs {
+		if structures.IsThreadStart(&m) {
+			tm, err := f.AllThreadMessages(ch.ID, m.ThreadTimestamp)
+			if err != nil {
+				return 0, fmt.Errorf("error reading thread messages: %w", err)
+			}
+			lg.Info("scanning thread messages", "num_messages", len(tm), "thread", m.ThreadTimestamp)
+			if n, err := scanMsgs(ctx, fp, cd, f, ch, tm); err != nil {
+				return total, err
+			} else {
+				total += n
+			}
+		}
+
+		// collect all missing files from the message.
+		var missing []slack.File
+		for _, ff := range m.Files {
+			name := filepath.Join(cd.Name(), fileproc.MattermostFilepath(ch, &ff))
+			lg := lg.With("file", name)
+			lg.Debug("checking file")
+			if fi, err := os.Stat(name); err != nil {
+				if os.IsNotExist(err) {
+					// file does not exist
+					lg.Debug("missing file")
+					missing = append(missing, ff)
+				} else {
+					lg.Error("error accessing file", "error", err)
+					// some other error
+					return total, fmt.Errorf("error accessing file: %w", err)
+				}
+			} else if fi.Size() == 0 {
+				// zero length files are considered missing
+				lg.Debug("zero length file")
+				missing = append(missing, ff)
+			} else {
+				lg.Debug("file OK")
+			}
+		}
+		if len(missing) > 0 {
+			total += len(missing)
+			lg.Info("found missing files", "num_files", len(missing))
+			if err := fp.Files(ctx, ch, m, missing); err != nil {
+				return total, fmt.Errorf("error processing files: %w", err)
+			}
+		}
+	}
+	return total, nil
+}
diff --git a/cmd/slackdump/internal/diag/tools.go b/cmd/slackdump/internal/diag/tools.go
index b84e1fab..47bb615f 100644
--- a/cmd/slackdump/internal/diag/tools.go
+++ b/cmd/slackdump/internal/diag/tools.go
@@ -31,6 +31,7 @@ Tools command contains different tools, running which may be requested if you op
 		// cmdSearch,
 		cmdThread,
 		cmdHydrate,
+		cmdRedownload,
 		// cmdWizDebug,
 	},
 }
diff --git a/internal/network/network.go b/internal/network/network.go
index 6011f74f..834450f5 100644
--- a/internal/network/network.go
+++ b/internal/network/network.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"log/slog"
 	"net"
 	"net/http"
@@ -117,6 +118,16 @@ func WithRetry(ctx context.Context, lim *rate.Limiter, maxAttempts int, fn func(
 			ne  *net.OpError // read tcp error: see #234
 		)
 		switch {
+		case errors.Is(cbErr, io.EOF):
+			// EOF is a transient error
+			delay := wait(attempt)
+			slog.WarnContext(ctx, "got EOF, sleeping", "error", cbErr, "delay", delay.String())
+			tracelogf(ctx, "info", "got EOF, sleeping %s (%s)", delay, cbErr)
+			if err := sleepCtx(ctx, delay); err != nil {
+				return err
+			}
+			slog.Debug("resuming after EOF")
+			continue
 		case errors.As(cbErr, &rle):
 			slog.InfoContext(ctx, "got rate limited, sleeping", "retry_after_sec", rle.RetryAfter, "error", cbErr)
 			tracelogf(ctx, "info", "got rate limited, sleeping %s (%s)", rle.RetryAfter, cbErr)
diff --git a/internal/network/network_test.go b/internal/network/network_test.go
index f783a068..d6be672f 100644
--- a/internal/network/network_test.go
+++ b/internal/network/network_test.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"net"
 	"net/http"
 	"net/http/httptest"
@@ -186,12 +187,10 @@ func TestWithRetry(t *testing.T) {
 			}
 		})
 	}
+	// setting fast wait function
 	t.Run("500 error handling", func(t *testing.T) {
-		t.Parallel()
 		setWaitFunc(func(attempt int) time.Duration { return 50 * time.Millisecond })
-		defer func() {
-			setWaitFunc(cubicWait)
-		}()
+		t.Cleanup(func() { setWaitFunc(cubicWait) })
 
 		codes := []int{500, 502, 503, 504, 598}
 		for _, code := range codes {
@@ -232,8 +231,6 @@ func TestWithRetry(t *testing.T) {
 			})
 		}
 		t.Run("404 error", func(t *testing.T) {
-			t.Parallel()
-
 			const (
 				testRetryCount = 1
 			)
@@ -265,8 +262,27 @@ func TestWithRetry(t *testing.T) {
 			}
 		})
 	})
+	t.Run("EOF error", func(t *testing.T) {
+		setWaitFunc(func(attempt int) time.Duration { return 50 * time.Millisecond })
+		t.Cleanup(func() { setWaitFunc(cubicWait) })
+
+		reterr := []error{io.EOF, io.EOF, nil}
+		var retries int
+
+		ctx := context.Background()
+		err := WithRetry(ctx, rate.NewLimiter(1, 1), 3, func() error {
+			err := reterr[retries]
+			if err != nil {
+				retries++
+			}
+			return err
+		})
+		assert.NoError(t, err)
+		assert.Equal(t, 2, retries)
+	})
 	t.Run("meaningful error message", func(t *testing.T) {
-		t.Parallel()
+		setWaitFunc(func(attempt int) time.Duration { return 50 * time.Millisecond })
+		t.Cleanup(func() { setWaitFunc(cubicWait) })
 		errFunc := func() error {
 			return slack.StatusCodeError{Code: 500, Status: "Internal Server Error"}
 		}
diff --git a/stream/conversation.go b/stream/conversation.go
index 94a8bf7d..b0f9d655 100644
--- a/stream/conversation.go
+++ b/stream/conversation.go
@@ -9,10 +9,11 @@ import (
 	"time"
 
 	"github.com/rusq/slack"
+	"golang.org/x/sync/errgroup"
+
 	"github.com/rusq/slackdump/v3/internal/network"
 	"github.com/rusq/slackdump/v3/internal/structures"
 	"github.com/rusq/slackdump/v3/processor"
-	"golang.org/x/sync/errgroup"
 )
 
 // SyncConversations fetches the conversations from the link which can be a
@@ -277,7 +278,7 @@ func (cs *Stream) thread(ctx context.Context, req request, callback func(mm []sl
 func procChanMsg(ctx context.Context, proc processor.Conversations, threadC chan<- request, channel *slack.Channel, isLast bool, mm []slack.Message) (int, error) {
 	lg := slog.With("channel_id", channel.ID, "is_last", isLast, "msg_count", len(mm))
 
-	var trs = make([]request, 0, len(mm))
+	trs := make([]request, 0, len(mm))
 	for i := range mm {
 		// collecting threads to get their count.  But we don't start
 		// processing them yet, before we send the messages with the number of
@@ -326,11 +327,12 @@ func procThreadMsg(ctx context.Context, proc processor.Conversations, channel *s
 		return err
 	}
 	if err := proc.ThreadMessages(ctx, channel.ID, head, threadOnly, isLast, rest); err != nil {
-		return fmt.Errorf("failed to process thread message id=%s, thread_ts=%s: %w", head.Msg.Timestamp, threadTS, err)
+		return fmt.Errorf("failed to process thread message id=%s, thread_ts=%s: %w", head.Timestamp, threadTS, err)
 	}
 	return nil
 }
 
+// procFiles proceses the files in slice of Messages msgs.
 func procFiles(ctx context.Context, proc processor.Filer, channel *slack.Channel, msgs ...slack.Message) error {
 	if len(msgs) == 0 {
 		return nil
@@ -416,7 +418,7 @@ func (cs *Stream) procChannelUsers(ctx context.Context, proc processor.ChannelIn
 func (cs *Stream) procChannelInfoWithUsers(ctx context.Context, proc processor.ChannelInformer, channelID, threadTS string) (*slack.Channel, error) {
 	var eg errgroup.Group
 
-	var chC = make(chan slack.Channel, 1)
+	chC := make(chan slack.Channel, 1)
 	eg.Go(func() error {
 		defer close(chC)
 		ch, err := cs.procChannelInfo(ctx, proc, channelID, threadTS)
@@ -427,7 +429,7 @@ func (cs *Stream) procChannelInfoWithUsers(ctx context.Context, proc processor.C
 		return nil
 	})
 
-	var uC = make(chan []string, 1)
+	uC := make(chan []string, 1)
 	eg.Go(func() error {
 		defer close(uC)
 		m, err := cs.procChannelUsers(ctx, proc, channelID, threadTS)
diff --git a/utils/count_chunks.sh b/utils/count_chunks.sh
new file mode 100644
index 00000000..715fe9c4
--- /dev/null
+++ b/utils/count_chunks.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+gzcat $1.json.gz| jq '.t' | awk '{count[$1]++}END{for(t in count)print t,count[t]}'
\ No newline at end of file