diff --git a/internal/bridge/user.go b/internal/bridge/user.go
index 3e34058c..b13868c3 100644
--- a/internal/bridge/user.go
+++ b/internal/bridge/user.go
@@ -441,9 +441,9 @@ func (bridge *Bridge) addUserWithVault(
 		ctx,
 		vault,
 		client,
+		bridge.reporter,
 		apiUser,
 		bridge.crashHandler,
-		bridge.reporter,
 		bridge.vault.SyncWorkers(),
 		bridge.vault.GetShowAllMail(),
 	)
diff --git a/internal/user/events.go b/internal/user/events.go
index 41b47a1e..adcda965 100644
--- a/internal/user/events.go
+++ b/internal/user/events.go
@@ -438,12 +438,12 @@ func (user *User) handleCreateMessageEvent(ctx context.Context, event proton.Mes
 		}).Info("Handling message created event")
 
 		return withAddrKR(user.apiUser, user.apiAddrs[event.Message.AddressID], user.vault.KeyPass(), func(_, addrKR *crypto.KeyRing) error {
-			buildRes, err := buildRFC822(user.apiLabels, full, addrKR)
+			update, err := buildRFC822(user.apiLabels, full, addrKR).update.unpack()
 			if err != nil {
 				return fmt.Errorf("failed to build RFC822 message: %w", err)
 			}
 
-			user.updateCh[full.AddressID].Enqueue(imap.NewMessagesCreated(buildRes.update))
+			user.updateCh[full.AddressID].Enqueue(imap.NewMessagesCreated(update))
 
 			return nil
 		})
@@ -493,16 +493,16 @@ func (user *User) handleUpdateDraftEvent(ctx context.Context, event proton.Messa
 		}
 
 		return withAddrKR(user.apiUser, user.apiAddrs[event.Message.AddressID], user.vault.KeyPass(), func(_, addrKR *crypto.KeyRing) error {
-			buildRes, err := buildRFC822(user.apiLabels, full, addrKR)
+			update, err := buildRFC822(user.apiLabels, full, addrKR).update.unpack()
 			if err != nil {
 				return fmt.Errorf("failed to build RFC822 draft: %w", err)
 			}
 
 			user.updateCh[full.AddressID].Enqueue(imap.NewMessageUpdated(
-				buildRes.update.Message,
-				buildRes.update.Literal,
-				buildRes.update.MailboxIDs,
-				buildRes.update.ParsedMessage,
+				update.Message,
+				update.Literal,
+				update.MailboxIDs,
+				update.ParsedMessage,
 			))
 
 			return nil
diff --git a/internal/user/sync.go b/internal/user/sync.go
index 611e23d2..173bbbf0 100644
--- a/internal/user/sync.go
+++ b/internal/user/sync.go
@@ -26,6 +26,7 @@ import (
 
 	"github.com/ProtonMail/gluon/imap"
 	"github.com/ProtonMail/gluon/queue"
+	"github.com/ProtonMail/gluon/reporter"
 	"github.com/ProtonMail/go-proton-api"
 	"github.com/ProtonMail/gopenpgp/v2/crypto"
 	"github.com/ProtonMail/proton-bridge/v3/internal/events"
@@ -36,6 +37,7 @@ import (
 	"github.com/google/uuid"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/exp/maps"
+	"golang.org/x/exp/slices"
 )
 
 const (
@@ -87,6 +89,7 @@ func (user *User) doSync(ctx context.Context) error {
 	return nil
 }
 
+// nolint:funlen
 func (user *User) sync(ctx context.Context) error {
 	return safe.RLockRet(func() error {
 		return withAddrKRs(user.apiUser, user.apiAddrs, user.vault.KeyPass(), func(_ *crypto.KeyRing, addrKRs map[string]*crypto.KeyRing) error {
@@ -109,10 +112,32 @@ func (user *User) sync(ctx context.Context) error {
 			if !user.vault.SyncStatus().HasMessages {
 				user.log.Info("Syncing messages")
 
+				// Determine which messages to sync.
+				messageIDs, err := user.client.GetMessageIDs(ctx, "")
+				if err != nil {
+					return fmt.Errorf("failed to get message IDs to sync: %w", err)
+				}
+
+				// Remove any messages that have already failed to sync.
+				messageIDs = xslices.Filter(messageIDs, func(messageID string) bool {
+					return !slices.Contains(user.vault.SyncStatus().FailedMessageIDs, messageID)
+				})
+
+				// Reverse the order of the message IDs so that the newest messages are synced first.
+				xslices.Reverse(messageIDs)
+
+				// If we have a message ID that we've already synced, then we can skip all messages before it.
+				if idx := xslices.Index(messageIDs, user.vault.SyncStatus().LastMessageID); idx >= 0 {
+					messageIDs = messageIDs[idx+1:]
+				}
+
+				// Sync the messages.
 				if err := syncMessages(
 					ctx,
 					user.ID(),
+					messageIDs,
 					user.client,
+					user.reporter,
 					user.vault,
 					user.apiLabels,
 					addrKRs,
@@ -183,7 +208,9 @@ func syncLabels(ctx context.Context, apiLabels map[string]proton.Label, updateCh
 func syncMessages(
 	ctx context.Context,
 	userID string,
+	messageIDs []string,
 	client *proton.Client,
+	sentry reporter.Reporter,
 	vault *vault.User,
 	apiLabels map[string]proton.Label,
 	addrKRs map[string]*crypto.KeyRing,
@@ -194,20 +221,6 @@ func syncMessages(
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
-	// Determine which messages to sync.
-	messageIDs, err := client.GetMessageIDs(ctx, "")
-	if err != nil {
-		return fmt.Errorf("failed to get message IDs to sync: %w", err)
-	}
-
-	// Reverse the order of the message IDs so that the newest messages are synced first.
-	xslices.Reverse(messageIDs)
-
-	// If we have a message ID that we've already synced, then we can skip all messages before it.
-	if idx := xslices.Index(messageIDs, vault.SyncStatus().LastMessageID); idx >= 0 {
-		messageIDs = messageIDs[idx+1:]
-	}
-
 	// Track the amount of time to process all the messages.
 	syncStartTime := time.Now()
 	defer func() { logrus.WithField("duration", time.Since(syncStartTime)).Info("Message sync completed") }()
@@ -222,14 +235,12 @@ func syncMessages(
 	flushers := make(map[string]*flusher, len(updateCh))
 
 	for addrID, updateCh := range updateCh {
-		flusher := newFlusher(updateCh, maxUpdateSize)
-
-		flushers[addrID] = flusher
+		flushers[addrID] = newFlusher(updateCh, maxUpdateSize)
 	}
 
 	// Create a reporter to report sync progress updates.
-	reporter := newReporter(userID, eventCh, len(messageIDs), time.Second)
-	defer reporter.done()
+	syncReporter := newSyncReporter(userID, eventCh, len(messageIDs), time.Second)
+	defer syncReporter.done()
 
 	type flushUpdate struct {
 		messageID string
@@ -267,7 +278,7 @@ func syncMessages(
 					return nil, ctx.Err()
 				}
 
-				return buildRFC822(apiLabels, msg, addrKRs[msg.AddressID])
+				return buildRFC822(apiLabels, msg, addrKRs[msg.AddressID]), nil
 			})
 			if err != nil {
 				errorCh <- err
@@ -289,7 +300,26 @@ func syncMessages(
 		defer close(flushUpdateCh)
 		for batch := range flushCh {
 			for _, res := range batch {
-				flushers[res.addressID].push(res.update)
+				if err := res.update.err(); err != nil {
+					if err := vault.AddFailedMessageID(res.messageID); err != nil {
+						logrus.WithError(err).Error("Failed to add failed message ID")
+					}
+
+					if err := sentry.ReportMessageWithContext("Failed to sync message", reporter.Context{
+						"messageID": res.messageID,
+						"error":     err,
+					}); err != nil {
+						logrus.WithError(err).Error("Failed to report message sync error")
+					}
+
+					continue
+				} else {
+					if err := vault.RemFailedMessageID(res.messageID); err != nil {
+						logrus.WithError(err).Error("Failed to remove failed message ID")
+					}
+
+					flushers[res.addressID].push(res.update.unwrap())
+				}
 			}
 
 			for _, flusher := range flushers {
@@ -321,7 +351,7 @@ func syncMessages(
 			return fmt.Errorf("failed to set last synced message ID: %w", err)
 		}
 
-		reporter.add(flushUpdate.batchLen)
+		syncReporter.add(flushUpdate.batchLen)
 	}
 
 	return <-errorCh
diff --git a/internal/user/sync_build.go b/internal/user/sync_build.go
index 897474a0..b5cfbd58 100644
--- a/internal/user/sync_build.go
+++ b/internal/user/sync_build.go
@@ -26,10 +26,39 @@ import (
 	"github.com/ProtonMail/proton-bridge/v3/pkg/message"
 )
 
+type result[T any] struct {
+	v T
+	e error
+}
+
+func resOk[T any](v T) result[T] {
+	return result[T]{v: v}
+}
+
+func resErr[T any](e error) result[T] {
+	return result[T]{e: e}
+}
+
+func (r *result[T]) unwrap() T {
+	if r.e != nil {
+		panic(r.err)
+	}
+
+	return r.v
+}
+
+func (r *result[T]) unpack() (T, error) {
+	return r.v, r.e
+}
+
+func (r *result[T]) err() error {
+	return r.e
+}
+
 type buildRes struct {
 	messageID string
 	addressID string
-	update    *imap.MessageCreated
+	update    result[*imap.MessageCreated]
 }
 
 func defaultJobOpts() message.JobOptions {
@@ -43,22 +72,22 @@ func defaultJobOpts() message.JobOptions {
 	}
 }
 
-func buildRFC822(apiLabels map[string]proton.Label, full proton.FullMessage, addrKR *crypto.KeyRing) (*buildRes, error) {
-	literal, err := message.BuildRFC822(addrKR, full.Message, full.AttData, defaultJobOpts())
-	if err != nil {
-		return nil, fmt.Errorf("failed to build message %s: %w", full.ID, err)
-	}
+func buildRFC822(apiLabels map[string]proton.Label, full proton.FullMessage, addrKR *crypto.KeyRing) *buildRes {
+	var update result[*imap.MessageCreated]
 
-	update, err := newMessageCreatedUpdate(apiLabels, full.MessageMetadata, literal)
-	if err != nil {
-		return nil, fmt.Errorf("failed to create IMAP update for message %s: %w", full.ID, err)
+	if literal, err := message.BuildRFC822(addrKR, full.Message, full.AttData, defaultJobOpts()); err != nil {
+		update = resErr[*imap.MessageCreated](fmt.Errorf("failed to build RFC822 for message %s: %w", full.ID, err))
+	} else if created, err := newMessageCreatedUpdate(apiLabels, full.MessageMetadata, literal); err != nil {
+		update = resErr[*imap.MessageCreated](fmt.Errorf("failed to create IMAP update for message %s: %w", full.ID, err))
+	} else {
+		update = resOk(created)
 	}
 
 	return &buildRes{
 		messageID: full.ID,
 		addressID: full.AddressID,
 		update:    update,
-	}, nil
+	}
 }
 
 func newMessageCreatedUpdate(
diff --git a/internal/user/sync_reporter.go b/internal/user/sync_reporter.go
index 3149e8cc..87722bb9 100644
--- a/internal/user/sync_reporter.go
+++ b/internal/user/sync_reporter.go
@@ -24,7 +24,7 @@ import (
 	"github.com/ProtonMail/proton-bridge/v3/internal/events"
 )
 
-type reporter struct {
+type syncReporter struct {
 	userID  string
 	eventCh *queue.QueuedChannel[events.Event]
 
@@ -36,8 +36,8 @@ type reporter struct {
 	freq time.Duration
 }
 
-func newReporter(userID string, eventCh *queue.QueuedChannel[events.Event], total int, freq time.Duration) *reporter {
-	return &reporter{
+func newSyncReporter(userID string, eventCh *queue.QueuedChannel[events.Event], total int, freq time.Duration) *syncReporter {
+	return &syncReporter{
 		userID:  userID,
 		eventCh: eventCh,
 
@@ -47,7 +47,7 @@ func newReporter(userID string, eventCh *queue.QueuedChannel[events.Event], tota
 	}
 }
 
-func (rep *reporter) add(delta int) {
+func (rep *syncReporter) add(delta int) {
 	rep.count += delta
 
 	if time.Since(rep.last) > rep.freq {
@@ -62,7 +62,7 @@ func (rep *reporter) add(delta int) {
 	}
 }
 
-func (rep *reporter) done() {
+func (rep *syncReporter) done() {
 	rep.eventCh.Enqueue(events.SyncProgress{
 		UserID:    rep.userID,
 		Progress:  1,
diff --git a/internal/user/user.go b/internal/user/user.go
index 28aebc0c..ccee8d65 100644
--- a/internal/user/user.go
+++ b/internal/user/user.go
@@ -29,7 +29,7 @@ import (
 	"github.com/ProtonMail/gluon/connector"
 	"github.com/ProtonMail/gluon/imap"
 	"github.com/ProtonMail/gluon/queue"
-	gluonReporter "github.com/ProtonMail/gluon/reporter"
+	"github.com/ProtonMail/gluon/reporter"
 	"github.com/ProtonMail/go-proton-api"
 	"github.com/ProtonMail/proton-bridge/v3/internal/async"
 	"github.com/ProtonMail/proton-bridge/v3/internal/events"
@@ -57,6 +57,7 @@ type User struct {
 
 	vault    *vault.User
 	client   *proton.Client
+	reporter reporter.Reporter
 	eventCh  *queue.QueuedChannel[events.Event]
 	sendHash *sendRecorder
 
@@ -72,8 +73,6 @@ type User struct {
 	updateCh     map[string]*queue.QueuedChannel[imap.Update]
 	updateChLock safe.RWMutex
 
-	reporter gluonReporter.Reporter
-
 	tasks     *async.Group
 	abortable async.Abortable
 	goSync    func()
@@ -92,9 +91,9 @@ func New(
 	ctx context.Context,
 	encVault *vault.User,
 	client *proton.Client,
+	reporter reporter.Reporter,
 	apiUser proton.User,
 	crashHandler async.PanicHandler,
-	reporter gluonReporter.Reporter,
 	syncWorkers int,
 	showAllMail bool,
 ) (*User, error) { //nolint:funlen
@@ -118,6 +117,7 @@ func New(
 
 		vault:    encVault,
 		client:   client,
+		reporter: reporter,
 		eventCh:  queue.NewQueuedChannel[events.Event](0, 0),
 		sendHash: newSendRecorder(sendEntryExpiry),
 
@@ -133,8 +133,6 @@ func New(
 		updateCh:     make(map[string]*queue.QueuedChannel[imap.Update]),
 		updateChLock: safe.NewRWMutex(),
 
-		reporter: reporter,
-
 		tasks:           async.NewGroup(context.Background(), crashHandler),
 		pollAPIEventsCh: make(chan chan struct{}),
 
diff --git a/internal/user/user_test.go b/internal/user/user_test.go
index 524c5297..66bba5e0 100644
--- a/internal/user/user_test.go
+++ b/internal/user/user_test.go
@@ -218,7 +218,7 @@ func withUser(tb testing.TB, ctx context.Context, _ *server.Server, m *proton.Ma
 	vaultUser, err := vault.AddUser(apiUser.ID, username, apiAuth.UID, apiAuth.RefreshToken, saltedKeyPass)
 	require.NoError(tb, err)
 
-	user, err := New(ctx, vaultUser, client, apiUser, nil, nil, vault.SyncWorkers(), true)
+	user, err := New(ctx, vaultUser, client, nil, apiUser, nil, vault.SyncWorkers(), true)
 	require.NoError(tb, err)
 	defer user.Close()
 
diff --git a/internal/vault/types_user.go b/internal/vault/types_user.go
index 9673d554..b58c76c2 100644
--- a/internal/vault/types_user.go
+++ b/internal/vault/types_user.go
@@ -60,9 +60,10 @@ func (mode AddressMode) String() string {
 }
 
 type SyncStatus struct {
-	HasLabels     bool
-	HasMessages   bool
-	LastMessageID string
+	HasLabels        bool
+	HasMessages      bool
+	LastMessageID    string
+	FailedMessageIDs []string
 }
 
 func (status SyncStatus) IsComplete() bool {
diff --git a/internal/vault/user.go b/internal/vault/user.go
index 38ee3ce9..50867f42 100644
--- a/internal/vault/user.go
+++ b/internal/vault/user.go
@@ -21,6 +21,8 @@ import (
 	"fmt"
 
 	"github.com/ProtonMail/gluon/imap"
+	"github.com/bradenaw/juniper/xslices"
+	"golang.org/x/exp/slices"
 )
 
 type User struct {
@@ -158,6 +160,24 @@ func (user *User) SetLastMessageID(messageID string) error {
 	})
 }
 
+// AddFailedMessageID adds a message ID to the list of failed message IDs.
+func (user *User) AddFailedMessageID(messageID string) error {
+	return user.vault.modUser(user.userID, func(data *UserData) {
+		if !slices.Contains(data.SyncStatus.FailedMessageIDs, messageID) {
+			data.SyncStatus.FailedMessageIDs = append(data.SyncStatus.FailedMessageIDs, messageID)
+		}
+	})
+}
+
+// RemFailedMessageID removes a message ID from the list of failed message IDs.
+func (user *User) RemFailedMessageID(messageID string) error {
+	return user.vault.modUser(user.userID, func(data *UserData) {
+		data.SyncStatus.FailedMessageIDs = xslices.Filter(data.SyncStatus.FailedMessageIDs, func(otherID string) bool {
+			return otherID != messageID
+		})
+	})
+}
+
 // ClearSyncStatus clears the user's sync status.
 func (user *User) ClearSyncStatus() error {
 	return user.vault.modUser(user.userID, func(data *UserData) {