diff --git a/app/db/models.py b/app/db/models.py
index 4be39bd..6c66abb 100644
--- a/app/db/models.py
+++ b/app/db/models.py
@@ -79,6 +79,16 @@ class Activity(Base):
     updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow, onupdate=utcnow)
 
 
+class SystemLogEntry(Base):
+    __tablename__ = "system_log_entries"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow, index=True)
+    source: Mapped[str] = mapped_column(String(64), nullable=False)
+    message: Mapped[str] = mapped_column(Text, nullable=False)
+    user_id: Mapped[int | None] = mapped_column(ForeignKey("sync_users.id", ondelete="SET NULL"))
+
+
 class SyncRun(Base):
     __tablename__ = "sync_runs"
 
diff --git a/app/db/repositories.py b/app/db/repositories.py
index 254d5b0..2535299 100644
--- a/app/db/repositories.py
+++ b/app/db/repositories.py
@@ -5,7 +5,7 @@ from sqlalchemy import and_, or_, select
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.orm import Session
 
-from app.db.models import Activity, ActivityStatus, SyncRun, SyncRunStatus, SyncUser, utcnow
+from app.db.models import Activity, ActivityStatus, SyncRun, SyncRunStatus, SystemLogEntry, SyncUser, utcnow
 
 
 @dataclass(frozen=True)
@@ -191,6 +191,26 @@ class ActivityRepository:
         )
 
 
+class SystemLogRepository:
+    def __init__(self, session: Session) -> None:
+        self.session = session
+
+    def add(self, *, source: str, message: str, user_id: int | None = None) -> SystemLogEntry:
+        entry = SystemLogEntry(source=source, message=message[:2000], user_id=user_id)
+        self.session.add(entry)
+        self.session.commit()
+        return entry
+
+    def list_recent(self, limit: int = 50) -> list[SystemLogEntry]:
+        return list(
+            self.session.scalars(
+                select(SystemLogEntry)
+                .order_by(SystemLogEntry.created_at.desc(), SystemLogEntry.id.desc())
+                .limit(limit)
+            )
+        )
+
+
 class SyncRunRepository:
     def __init__(self, session: Session) -> None:
         self.session = session
diff --git a/app/sync/manager.py b/app/sync/manager.py
index 264c7ed..304d577 100644
--- a/app/sync/manager.py
+++ b/app/sync/manager.py
@@ -6,7 +6,7 @@ from pathlib import Path
 from typing import Any, Callable
 
 from app.db.models import ActivityStatus, HealthState, SyncRunStatus
-from app.db.repositories import ActivityRepository, SyncRunRepository, UserRepository
+from app.db.repositories import ActivityRepository, SyncRunRepository, SystemLogRepository, UserRepository
 from app.fit.rewriter import FitFormatError
 from app.garmin.uploader import (
     GarminAuthError,
@@ -76,7 +76,7 @@ class SyncManager:
         self._locks: dict[int, asyncio.Lock] = {}
         self._locks_guard = asyncio.Lock()
 
-    def _notify_action_required(self, user: Any, message: str | None) -> None:
+    def _notify_action_required(self, session: Any, user: Any, message: str | None) -> None:
         if self.notifier is None or not user.notify_email_enabled or not user.notification_email:
             return
         try:
@@ -85,10 +85,21 @@ class SyncManager:
                 subject=f"MyWhoosh-Garmin Sync: action required for {user.name}",
                 body=message or "Your sync requires attention. Check the dashboard for details.",
             )
-        except Exception:
+        except Exception as exc:
             logger.warning(
                 "sync_user: failed to send action-required notification for user %s", user.id, exc_info=True
             )
+            try:
+                SystemLogRepository(session).add(
+                    source="email_notification",
+                    message=(
+                        f"Failed to email {user.notification_email} for user {user.id} ({user.name}): "
+                        f"{type(exc).__name__}: {exc}"
+                    ),
+                    user_id=user.id,
+                )
+            except Exception:
+                logger.warning("sync_user: failed to record email-notification failure in system log", exc_info=True)
 
     async def _lock_for(self, user_id: int) -> asyncio.Lock:
         async with self._locks_guard:
@@ -389,7 +400,7 @@ class SyncManager:
                     )
                     session.commit()
                     if user.action_reason is not None and user.action_reason != previous_action_reason:
-                        self._notify_action_required(user, summary_error)
+                        self._notify_action_required(session, user, summary_error)
                     return SyncOutcome(
                         user_id=user.id,
                         status=status.value,
diff --git a/app/web/operations.py b/app/web/operations.py
index c4433a4..507ba2c 100644
--- a/app/web/operations.py
+++ b/app/web/operations.py
@@ -5,7 +5,7 @@ from sqlalchemy import func, select
 from app.auth.admin import require_admin
 from app.auth.csrf import ensure_csrf_token, validate_csrf
 from app.db.models import Activity
-from app.db.repositories import ActivityRepository, UserRepository
+from app.db.repositories import ActivityRepository, SystemLogRepository, UserRepository
 from app.sync.manager import SyncAlreadyRunning
 from app.web.routes import templates
 
@@ -103,6 +103,7 @@ def system_page(request: Request):
     with request.app.state.session_factory() as session:
         user_count = len(UserRepository(session).list_all())
         activity_count = session.scalar(select(func.count()).select_from(Activity)) or 0
+        log_entries = SystemLogRepository(session).list_recent(limit=50)
     return templates.TemplateResponse(request, "system.html", {
         "csrf_token": ensure_csrf_token(request),
         "app_version": APP_VERSION,
@@ -111,4 +112,5 @@ def system_page(request: Request):
         "next_tick": scheduler.next_tick,
         "user_count": user_count,
         "activity_count": activity_count,
+        "log_entries": log_entries,
     })
diff --git a/app/web/templates/system.html b/app/web/templates/system.html
index 945ea83..94442ff 100644
--- a/app/web/templates/system.html
+++ b/app/web/templates/system.html
@@ -31,4 +31,30 @@
     <input type="hidden" name="csrf_token" value="{{ csrf_token }}">
     <button type="submit">Sync all now</button>
 </form>
+
+<h2>System log</h2>
+<div class="card">
+    {% if log_entries %}
+    <table>
+        <thead>
+            <tr>
+                <th>Time</th>
+                <th>Source</th>
+                <th>Message</th>
+            </tr>
+        </thead>
+        <tbody>
+            {% for entry in log_entries %}
+            <tr>
+                <td>{{ entry.created_at }}</td>
+                <td>{{ entry.source }}</td>
+                <td>{{ entry.message }}</td>
+            </tr>
+            {% endfor %}
+        </tbody>
+    </table>
+    {% else %}
+    <p class="empty-state">No system log entries.</p>
+    {% endif %}
+</div>
 {% endblock %}
diff --git a/tests/conftest.py b/tests/conftest.py
index 9d1ed73..686b514 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -9,7 +9,7 @@ from sqlalchemy.pool import StaticPool
 
 from app.config import Settings
 from app.db.models import Activity, Base, HealthState
-from app.db.repositories import ActivityRepository, SyncRunRepository, UserRepository
+from app.db.repositories import ActivityRepository, SyncRunRepository, SystemLogRepository, UserRepository
 from app.main import create_app
 
 
@@ -44,6 +44,11 @@ def sync_run_repository(db_session: Session) -> SyncRunRepository:
     return SyncRunRepository(db_session)
 
 
+@pytest.fixture
+def system_log_repository(db_session: Session) -> SystemLogRepository:
+    return SystemLogRepository(db_session)
+
+
 @pytest.fixture
 def app(tmp_path: Path):
     settings = Settings(
diff --git a/tests/db/test_repositories.py b/tests/db/test_repositories.py
index 130deec..9d4d67e 100644
--- a/tests/db/test_repositories.py
+++ b/tests/db/test_repositories.py
@@ -64,3 +64,32 @@ def test_activity_external_id_is_unique_per_user(user_repository, activity_repos
     assert inserted_again is False
     assert created.id == same.id
     assert same.status == ActivityStatus.DISCOVERED
+
+
+def test_system_log_lists_most_recent_first(system_log_repository, user_repository) -> None:
+    user = user_repository.create(
+        name="Max",
+        enabled=True,
+        health_state=HealthState.HEALTHY,
+        mywhoosh_email_enc="mw-1",
+        mywhoosh_password_enc="mw-pw-1",
+        garmin_email_enc="g-1",
+        garmin_password_enc="g-pw-1",
+    )
+    system_log_repository.add(source="email_notification", message="first failure", user_id=user.id)
+    system_log_repository.add(source="email_notification", message="second failure", user_id=user.id)
+
+    entries = system_log_repository.list_recent()
+
+    assert [entry.message for entry in entries] == ["second failure", "first failure"]
+    assert entries[0].source == "email_notification"
+    assert entries[0].user_id == user.id
+
+
+def test_system_log_respects_limit(system_log_repository) -> None:
+    for i in range(5):
+        system_log_repository.add(source="test", message=f"entry {i}")
+
+    entries = system_log_repository.list_recent(limit=2)
+
+    assert len(entries) == 2
diff --git a/tests/sync/test_manager.py b/tests/sync/test_manager.py
index 8508e7d..c9d694f 100644
--- a/tests/sync/test_manager.py
+++ b/tests/sync/test_manager.py
@@ -4,7 +4,7 @@ import pytest
 from sqlalchemy import select
 
 from app.db.models import ActivityStatus, HealthState, SyncRun, SyncRunStatus, SyncUser
-from app.db.repositories import UserRepository
+from app.db.repositories import SystemLogRepository, UserRepository
 from app.garmin.uploader import UploadResult
 from app.mywhoosh.client import MyWhooshDeviceConflictError
 from app.mywhoosh.models import MyWhooshActivity
@@ -305,6 +305,44 @@ async def test_does_not_renotify_for_unresolved_unchanged_reason(session_factory
     assert len(notifier.sent) == 1
 
 
+class FailingNotifier:
+    def send(self, *, to_address: str, subject: str, body: str) -> None:
+        raise RuntimeError("SMTP connection refused")
+
+
+@pytest.mark.asyncio
+async def test_email_send_failure_is_recorded_in_system_log_and_does_not_break_sync(
+    session_factory, cipher, settings
+) -> None:
+    with session_factory() as session:
+        user = _create_user(session, cipher)
+        user.notify_email_enabled = True
+        user.notification_email = "alerts@example.com"
+        session.commit()
+        user_id = user.id
+
+    manager = SyncManager(
+        session_factory=session_factory,
+        credential_cipher=cipher,
+        settings=settings,
+        mywhoosh_factory=lambda token_store: DeviceConflictMyWhooshClient(),
+        garmin_factory=lambda email, password, tokenstore: FakeGarminUploader(),
+        fit_converter=FakeFitConverter(),
+        notifier=FailingNotifier(),
+    )
+
+    outcome = await manager.sync_user(user_id)
+    assert outcome.status == "failed"
+
+    with session_factory() as session:
+        entries = SystemLogRepository(session).list_recent()
+        assert len(entries) == 1
+        assert entries[0].source == "email_notification"
+        assert entries[0].user_id == user_id
+        assert "SMTP connection refused" in entries[0].message
+        assert "alerts@example.com" in entries[0].message
+
+
 @pytest.mark.asyncio
 async def test_mfa_code_reaches_real_garmin_uploader_via_sync_manager(
     session_factory, cipher, settings, seeded_user: SyncUser
diff --git a/tests/web/test_operations.py b/tests/web/test_operations.py
index 5f14c5f..1e3f527 100644
--- a/tests/web/test_operations.py
+++ b/tests/web/test_operations.py
@@ -1,5 +1,7 @@
 from fastapi.testclient import TestClient
 
+from app.db.repositories import SystemLogRepository
+
 
 def test_manual_sync_calls_shared_manager(authenticated_client, fake_sync_manager) -> None:
     response = authenticated_client.post(
@@ -60,3 +62,30 @@ def test_system_page_shows_scheduler_state(app, authenticated_client) -> None:
     assert "1.0.0" in response.text
     assert "5" in response.text  # sync_interval_minutes
     assert "0" in response.text  # user_count / activity_count fresh DB
+
+
+class _FakeScheduler:
+    def __init__(self) -> None:
+        self.last_tick = None
+        self.next_tick = None
+
+
+def test_system_page_shows_empty_log_state(app, authenticated_client) -> None:
+    app.state.scheduler = _FakeScheduler()
+
+    response = authenticated_client.get("/system")
+    assert response.status_code == 200
+    assert "No system log entries" in response.text
+
+
+def test_system_page_shows_recorded_log_entries(app, authenticated_client) -> None:
+    app.state.scheduler = _FakeScheduler()
+    with app.state.session_factory() as session:
+        SystemLogRepository(session).add(
+            source="email_notification", message="Failed to email alerts@example.com: SMTP timeout"
+        )
+
+    response = authenticated_client.get("/system")
+    assert response.status_code == 200
+    assert "email_notification" in response.text
+    assert "SMTP timeout" in response.text