Strip profile session restore when configure batch carries a start_url

server/cmd/api/api/chromium_configure.go

@@ -158,6 +158,11 @@ func (s *ApiService) ChromiumConfigure(ctx context.Context, request oapi.Chromiu
 			if err != nil {
 				return cfg500ConfigureStep(chromiumConfigureStepProfile, err.Error()), nil
 			}
+			if spec.needsNav {
+				if err := stripProfileSessionRestore(preparedProfile); err != nil {
+					return cfg500ConfigureStep(chromiumConfigureStepProfile, err.Error()), nil
+				}
+			}
 			if err := chromiumInstallPreparedProfile(preparedProfile); err != nil {
 				return cfg500ConfigureStep(chromiumConfigureStepProfile, err.Error()), nil
 			}
@@ -564,6 +569,16 @@ func chromiumPrepareProfileArchive(profilePath string, strip int) (preparedDir s
 	return preparedDir, cleanup, nil
 }
 
+// stripProfileSessionRestore deletes the prepared profile's Default/Sessions so
+// Chrome cannot restore its saved tabs after the restart and race the start_url
+// navigation. Only the live copy is touched; the stored archive is unchanged.
+func stripProfileSessionRestore(preparedDir string) error {
+	if err := os.RemoveAll(filepath.Join(preparedDir, "Default", "Sessions")); err != nil {
+		return fmt.Errorf("strip profile session restore: %w", err)
+	}
+	return nil
+}
+
 func chromiumInstallPreparedProfile(preparedDir string) error {
 	if preparedDir == "" {
 		return nil

server/cmd/api/api/chromium_configure_test.go

@@ -5,6 +5,8 @@ import (
 	"errors"
 	"io"
 	"mime/multipart"
+	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 
@@ -76,6 +78,24 @@ func TestChromiumStartURLSpec(t *testing.T) {
 	require.NotEmpty(t, errs)
 }
 
+func TestStripProfileSessionRestore(t *testing.T) {
+	prepared := t.TempDir()
+	sessions := filepath.Join(prepared, "Default", "Sessions")
+	require.NoError(t, os.MkdirAll(sessions, 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(sessions, "Session_123"), []byte("tabs"), 0o644))
+	require.NoError(t, os.WriteFile(filepath.Join(prepared, "Default", "Preferences"), []byte("{}"), 0o644))
+
+	require.NoError(t, stripProfileSessionRestore(prepared))
+
+	_, err := os.Stat(sessions)
+	require.True(t, os.IsNotExist(err))
+	_, err = os.Stat(filepath.Join(prepared, "Default", "Preferences"))
+	require.NoError(t, err)
+
+	// Absent Sessions directory is a no-op, not an error.
+	require.NoError(t, stripProfileSessionRestore(prepared))
+}
+
 func TestChromiumValidateFlags(t *testing.T) {
 	valid := `{"flags":["--kiosk"]}`
 	plan, err := chromiumValidateFlags(&valid)