diff --git a/app/botnew/spam.go b/app/botnew/spam.go
index 4ee9b4b9..78b448e1 100644
--- a/app/botnew/spam.go
+++ b/app/botnew/spam.go
@@ -1,6 +1,7 @@
 package bot
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -147,42 +148,42 @@ func (s *SpamFilter) watch(ctx context.Context) error {
 	return nil
 }
 
-func (s *SpamFilter) reloadSamples() error {
+func (s *SpamFilter) reloadSamples() (err error) {
 	log.Printf("[DEBUG] reloading samples")
-	// open all files we need to reload
-	exclReader, err := os.Open(s.params.ExcludedTokensFile)
-	if err != nil {
-		return fmt.Errorf("failed to open excluded tokens file %s: %w", s.params.ExcludedTokensFile, err)
-	}
-	defer exclReader.Close()
 
-	spamReader, err := os.Open(s.params.SpamSamplesFile)
-	if err != nil {
-		return fmt.Errorf("failed to open spam samples file %s: %w", s.params.SpamSamplesFile, err)
+	var exclReader, spamReader, hamReader, stopWordsReader, spamDynamicReader, hamDynamicReader io.ReadCloser
+
+	// open mandatory spam and ham samples files
+	if spamReader, err = os.Open(s.params.SpamSamplesFile); err != nil {
+		return fmt.Errorf("failed to open spam samples file %q: %w", s.params.SpamSamplesFile, err)
 	}
 	defer spamReader.Close()
 
-	hamReader, err := os.Open(s.params.HamSamplesFile)
-	if err != nil {
-		return fmt.Errorf("failed to open ham samples file %s: %w", s.params.HamSamplesFile, err)
+	if hamReader, err = os.Open(s.params.HamSamplesFile); err != nil {
+		return fmt.Errorf("failed to open ham samples file %q: %w", s.params.HamSamplesFile, err)
 	}
 	defer hamReader.Close()
 
-	stopWordsReader, err := os.Open(s.params.StopWordsFile)
-	if err != nil {
-		return fmt.Errorf("failed to open stop words file %s: %w", s.params.StopWordsFile, err)
+	// stop-words are optional
+	if stopWordsReader, err = os.Open(s.params.StopWordsFile); err != nil {
+		stopWordsReader = io.NopCloser(bytes.NewReader([]byte("")))
 	}
 	defer stopWordsReader.Close()
 
-	spamDynamicReader, err := os.Open(s.params.SpamDynamicFile)
-	if err != nil {
-		return fmt.Errorf("failed to open spam dynamic file %s: %w", s.params.SpamDynamicFile, err)
+	// excluded tokens are optional
+	if exclReader, err = os.Open(s.params.ExcludedTokensFile); err != nil {
+		exclReader = io.NopCloser(bytes.NewReader([]byte("")))
+	}
+	defer exclReader.Close()
+
+	// dynamic samples are optional
+	if spamDynamicReader, err = os.Open(s.params.SpamDynamicFile); err != nil {
+		spamDynamicReader = io.NopCloser(bytes.NewReader([]byte("")))
 	}
 	defer spamDynamicReader.Close()
 
-	hamDynamicReader, err := os.Open(s.params.HamDynamicFile)
-	if err != nil {
-		return fmt.Errorf("failed to open ham dynamic file %s: %w", s.params.HamDynamicFile, err)
+	if hamDynamicReader, err = os.Open(s.params.HamDynamicFile); err != nil {
+		hamDynamicReader = io.NopCloser(bytes.NewReader([]byte("")))
 	}
 	defer hamDynamicReader.Close()
 
diff --git a/app/botnew/spam_test.go b/app/botnew/spam_test.go
index 8d2d9b78..e682ede9 100644
--- a/app/botnew/spam_test.go
+++ b/app/botnew/spam_test.go
@@ -1,9 +1,13 @@
 package bot
 
 import (
+	"errors"
+	"io"
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/umputun/tg-spam/app/botnew/mocks"
 	"github.com/umputun/tg-spam/lib"
@@ -41,3 +45,115 @@ func TestSpamFilter_OnMessage(t *testing.T) {
 	})
 
 }
+
+func TestSpamFilter_reloadSamples(t *testing.T) {
+	var osOpen = os.Open // Mock for os.Open function
+
+	// Mock os.Open
+	openOriginal := osOpen
+	defer func() { osOpen = openOriginal }()
+	osOpen = func(name string) (*os.File, error) {
+		if name == "fail" {
+			return nil, errors.New("open error")
+		}
+		if name == "notfound" {
+			return nil, os.ErrNotExist
+		}
+		return os.Open(os.DevNull) // Open a harmless file for other cases
+	}
+
+	mockDirector := &mocks.DetectorMock{
+		LoadSamplesFunc: func(exclReader io.Reader, spamReaders []io.Reader, hamReaders []io.Reader) (lib.LoadResult, error) {
+			return lib.LoadResult{}, nil
+		},
+		LoadStopWordsFunc: func(readers ...io.Reader) (lib.LoadResult, error) {
+			return lib.LoadResult{}, nil
+		},
+	}
+
+	s := NewSpamFilter(mockDirector, SpamParams{
+		SpamSamplesFile:    "/dev/null",
+		HamSamplesFile:     "/dev/null",
+		StopWordsFile:      "optional",
+		ExcludedTokensFile: "optional",
+		SpamDynamicFile:    "optional",
+		HamDynamicFile:     "optional",
+	})
+
+	tests := []struct {
+		name        string
+		modify      func()
+		expectedErr error
+	}{
+		{
+			name:        "Successful execution",
+			modify:      func() {},
+			expectedErr: nil,
+		},
+		{
+			name: "Spam samples file open failure",
+			modify: func() {
+				s.params.SpamSamplesFile = "fail"
+			},
+			expectedErr: errors.New("failed to open spam samples file \"fail\": open fail: no such file or directory"),
+		},
+		{
+			name: "Ham samples file open failure",
+			modify: func() {
+				s.params.HamSamplesFile = "fail"
+			},
+			expectedErr: errors.New("failed to open ham samples file \"fail\": open fail: no such file or directory"),
+		},
+		{
+			name: "Stop words file not found",
+			modify: func() {
+				s.params.StopWordsFile = "notfound"
+			},
+			expectedErr: nil,
+		},
+		{
+			name: "Excluded tokens file not found",
+			modify: func() {
+				s.params.ExcludedTokensFile = "notfound"
+			},
+			expectedErr: nil,
+		},
+		{
+			name: "Spam dynamic file not found",
+			modify: func() {
+				s.params.SpamDynamicFile = "notfound"
+			},
+			expectedErr: nil,
+		},
+		{
+			name: "Ham dynamic file not found",
+			modify: func() {
+				s.params.HamDynamicFile = "notfound"
+			},
+			expectedErr: nil,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			// Reset to default values before each test
+			s = NewSpamFilter(mockDirector, SpamParams{
+				SpamSamplesFile:    "/dev/null",
+				HamSamplesFile:     "/dev/null",
+				StopWordsFile:      "optional",
+				ExcludedTokensFile: "optional",
+				SpamDynamicFile:    "optional",
+				HamDynamicFile:     "optional",
+			})
+			tc.modify()
+			err := s.reloadSamples()
+
+			if tc.expectedErr != nil {
+				require.Error(t, err)
+				assert.Equal(t, tc.expectedErr.Error(), err.Error())
+			} else {
+				assert.NoError(t, err)
+			}
+		})
+	}
+}