diff --git a/redmine_reporter/client.py b/redmine_reporter/client.py
index dbe6b69..14a432f 100644
--- a/redmine_reporter/client.py
+++ b/redmine_reporter/client.py
@@ -1,3 +1,4 @@
+import sys
 from datetime import datetime, timezone
 from typing import Any, Dict, List, Optional, Tuple, Union
 
@@ -121,7 +122,14 @@ def _load_time_entry_activities(redmine: Redmine) -> Dict[int, str]:
     try:
         activities = redmine.enumeration.filter(resource="time_entry_activities")
         return {int(a.id): str(a.name) for a in activities}
-    except Exception:
+    except Exception as exc:
+        # #61: не глотаем сбой молча — предупреждаем, что разбивка по
+        # активностям будет построена по сырым данным из самих entries.
+        print(
+            f"⚠️  Could not load time entry activities: {exc}. "
+            "Activity names will be taken from time entries.",
+            file=sys.stderr,
+        )
         return {}
 
 
@@ -346,6 +354,20 @@ def fetch_issues_with_spent_time(
     except Exception as exc:
         raise RedmineAPIError(_format_redmine_error(exc), original=exc) from exc
 
+    # #61: задачи могли не вернуться из issue.filter (нет прав / удалены) —
+    # предупреждаем о выпавших задачах и потерянных часах, но строим отчёт
+    # по доступным данным.
+    returned_ids = {issue.id for issue in issues}
+    missing_ids = sorted(issue_ids - returned_ids)
+    if missing_ids:
+        lost_hours = sum(spent_time[iid] for iid in missing_ids)
+        print(
+            f"⚠️  {len(missing_ids)} issue(s) unavailable (no access or deleted; "
+            f"IDs: {', '.join(str(i) for i in missing_ids)}): "
+            f"{lost_hours:g}h excluded from the report.",
+            file=sys.stderr,
+        )
+
     # Сопоставляем задачи с суммарным временем.
     # Сортировка выполняется в report_builder.build_grouped_report,
     # здесь оставляем порядок API как есть.
diff --git a/tests/test_client.py b/tests/test_client.py
index 204eb7f..35accff 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -969,3 +969,111 @@ def test_dedup_accepts_naive_cutoff(mock_redmine_class):
 
     assert result is not None
     assert [r[0].id for r in result] == [2]
+
+
+# -- #61: предупреждения о молчаливой потере данных --
+
+
+@mock.patch.dict(os.environ, PASSWORD_ENV, clear=True)
+@mock.patch("redmine_reporter.client.Redmine")
+def test_fetch_warns_about_missing_issues(mock_redmine_class, capsys):
+    """Задачи, не вернувшиеся из issue.filter, попадают в warning в stderr (#61).
+
+    Отчёт при этом строится по доступным данным — это предупреждение, не ошибка.
+    """
+    mock_redmine = mock_redmine_class.return_value
+    _configure_current_user(mock_redmine, user_id=123)
+
+    def make_entry(issue_id, hours):
+        e = mock.MagicMock()
+        e.issue.id = issue_id
+        e.hours = hours
+        return e
+
+    mock_redmine.time_entry.filter.return_value = [
+        make_entry(1, 1.0),
+        make_entry(2, 2.5),
+        make_entry(3, 0.75),
+    ]
+
+    mock_issue1 = mock.MagicMock()
+    mock_issue1.id = 1
+    mock_issue1.project = "P"
+    mock_issue1.subject = "T"
+    mock_issue1.status = "New"
+    # Задачи 2 и 3 не вернулись (нет прав / удалены)
+    mock_redmine.issue.filter.return_value = [mock_issue1]
+
+    result = fetch_issues_with_spent_time("2026-01-01", "2026-01-31")
+
+    assert result is not None
+    assert [r[0].id for r in result] == [1]
+
+    captured = capsys.readouterr()
+    assert "2" in captured.err
+    assert "3" in captured.err
+    assert "3.25" in captured.err  # сумма потерянных часов 2.5 + 0.75
+
+
+@mock.patch.dict(os.environ, PASSWORD_ENV, clear=True)
+@mock.patch("redmine_reporter.client.Redmine")
+def test_fetch_no_warning_when_all_issues_returned(mock_redmine_class, capsys):
+    """Если все задачи вернулись, stderr остаётся чистым (#61)."""
+    mock_redmine = mock_redmine_class.return_value
+    _configure_current_user(mock_redmine, user_id=123)
+
+    e = mock.MagicMock()
+    e.issue.id = 1
+    e.hours = 1.0
+    mock_redmine.time_entry.filter.return_value = [e]
+
+    mock_issue1 = mock.MagicMock()
+    mock_issue1.id = 1
+    mock_redmine.issue.filter.return_value = [mock_issue1]
+
+    result = fetch_issues_with_spent_time("2026-01-01", "2026-01-31")
+
+    assert result is not None
+    captured = capsys.readouterr()
+    assert captured.err == ""
+
+
+@mock.patch.dict(os.environ, PASSWORD_ENV, clear=True)
+@mock.patch("redmine_reporter.client.Redmine")
+def test_fetch_warns_when_activities_lookup_fails(mock_redmine_class, capsys):
+    """Сбой справочника активностей — warning в stderr, отчёт строится (#61)."""
+    mock_redmine = mock_redmine_class.return_value
+    _configure_current_user(mock_redmine, user_id=123)
+    mock_redmine.enumeration.filter.side_effect = Exception("enumeration boom")
+
+    e = mock.MagicMock()
+    e.issue.id = 1
+    e.hours = 1.0
+    e.activity.id = 9
+    e.activity.name = "Dev"
+    mock_redmine.time_entry.filter.return_value = [e]
+
+    mock_issue1 = mock.MagicMock()
+    mock_issue1.id = 1
+    mock_redmine.issue.filter.return_value = [mock_issue1]
+
+    result = fetch_issues_with_spent_time("2026-01-01", "2026-01-31", by_activity=True)
+
+    assert result is not None
+    assert result[0][2] == {"Dev": 1.0}  # fallback на имя из самого entry
+
+    captured = capsys.readouterr()
+    assert "activit" in captured.err.lower()
+
+
+def test_load_time_entry_activities_returns_empty_on_failure(capsys):
+    """_load_time_entry_activities возвращает {} и пишет warning при сбое (#61)."""
+    from redmine_reporter.client import _load_time_entry_activities
+
+    redmine = mock.MagicMock()
+    redmine.enumeration.filter.side_effect = Exception("enumeration boom")
+
+    assert _load_time_entry_activities(redmine) == {}
+
+    captured = capsys.readouterr()
+    assert "activit" in captured.err.lower()