diff --git a/connector/dummy.go b/connector/dummy.go
index f9c47989..f280f2c9 100644
--- a/connector/dummy.go
+++ b/connector/dummy.go
@@ -55,6 +55,8 @@ type Dummy struct {
 
 	// uidValidity holds the global UID validity.
 	uidValidity imap.UID
+
+	allowMessageCreateWithUnknownMailboxID bool
 }
 
 func NewDummy(usernames []string, password []byte, period time.Duration, flags, permFlags, attrs imap.FlagSet) *Dummy {
@@ -162,7 +164,7 @@ func (conn *Dummy) CreateMessage(ctx context.Context, mboxID imap.MailboxID, lit
 		date,
 	)
 
-	update := imap.NewMessagesCreated(&imap.MessageCreated{
+	update := imap.NewMessagesCreated(conn.allowMessageCreateWithUnknownMailboxID, &imap.MessageCreated{
 		Message:       message,
 		Literal:       literal,
 		MailboxIDs:    []imap.MailboxID{mboxID},
@@ -277,7 +279,7 @@ func (conn *Dummy) Sync(ctx context.Context) error {
 		updates = append(updates, update)
 	}
 
-	update := imap.NewMessagesCreated(updates...)
+	update := imap.NewMessagesCreated(conn.allowMessageCreateWithUnknownMailboxID, updates...)
 	defer update.WaitContext(ctx)
 
 	conn.updateCh <- update
diff --git a/connector/dummy_simulate.go b/connector/dummy_simulate.go
index db9d2e8e..7c165f33 100644
--- a/connector/dummy_simulate.go
+++ b/connector/dummy_simulate.go
@@ -79,7 +79,7 @@ func (conn *Dummy) MessageCreated(message imap.Message, literal []byte, mboxIDs
 		mboxIDs: mboxIDMap,
 	}
 
-	update := imap.NewMessagesCreated(&imap.MessageCreated{
+	update := imap.NewMessagesCreated(conn.allowMessageCreateWithUnknownMailboxID, &imap.MessageCreated{
 		Message:       message,
 		Literal:       literal,
 		MailboxIDs:    mboxIDs,
@@ -126,7 +126,7 @@ func (conn *Dummy) MessagesCreated(messages []imap.Message, literals [][]byte, m
 		})
 	}
 
-	conn.pushUpdate(imap.NewMessagesCreated(updates...))
+	conn.pushUpdate(imap.NewMessagesCreated(conn.allowMessageCreateWithUnknownMailboxID, updates...))
 
 	return nil
 }
@@ -224,3 +224,7 @@ func (conn *Dummy) UIDValidityBumped() {
 func (conn *Dummy) Flush() {
 	conn.ticker.Poll()
 }
+
+func (conn *Dummy) SetAllowMessageCreateWithUnknownMailboxID(value bool) {
+	conn.allowMessageCreateWithUnknownMailboxID = value
+}
diff --git a/imap/update_message_created.go b/imap/update_message_created.go
index 3fb8d715..9a3e0506 100644
--- a/imap/update_message_created.go
+++ b/imap/update_message_created.go
@@ -44,6 +44,9 @@ type MessagesCreated struct {
 	*updateWaiter
 
 	Messages []*MessageCreated
+
+	// IgnoreUnknownMailboxIDs will allow message creation when one or more MailboxIDs are not yet known when set to true.
+	IgnoreUnknownMailboxIDs bool
 }
 
 type MessageCreated struct {
@@ -53,10 +56,11 @@ type MessageCreated struct {
 	ParsedMessage *ParsedMessage
 }
 
-func NewMessagesCreated(updates ...*MessageCreated) *MessagesCreated {
+func NewMessagesCreated(ignoreUnknownMailboxIDs bool, updates ...*MessageCreated) *MessagesCreated {
 	return &MessagesCreated{
-		updateWaiter: newUpdateWaiter(),
-		Messages:     updates,
+		updateWaiter:            newUpdateWaiter(),
+		Messages:                updates,
+		IgnoreUnknownMailboxIDs: ignoreUnknownMailboxIDs,
 	}
 }
 
diff --git a/internal/backend/connector_updates.go b/internal/backend/connector_updates.go
index 36a7bfd4..fbc2cd70 100644
--- a/internal/backend/connector_updates.go
+++ b/internal/backend/connector_updates.go
@@ -244,6 +244,13 @@ func (user *user) applyMessagesCreated(ctx context.Context, update *imap.Message
 				if !ok {
 					internalMBoxID, err := db.GetMailboxIDWithRemoteID(ctx, client, mboxID)
 					if err != nil {
+						// If a mailbox doesn't exist and we are allowed to skip move to next mailbox.
+						if update.IgnoreUnknownMailboxIDs {
+							logrus.WithField("MailboxID", mboxID.ShortID()).
+								WithField("MessageID", message.Message.ID.ShortID()).
+								Warn("Unknown Mailbox ID, skipping add to mailbox")
+							continue
+						}
 						return err
 					}
 
diff --git a/tests/session_test.go b/tests/session_test.go
index 73c89895..5443b289 100644
--- a/tests/session_test.go
+++ b/tests/session_test.go
@@ -33,6 +33,8 @@ type Connector interface {
 	MailboxDeleted(imap.MailboxID) error
 	SetMailboxVisible(imap.MailboxID, bool)
 
+	SetAllowMessageCreateWithUnknownMailboxID(value bool)
+
 	MessageCreated(imap.Message, []byte, []imap.MailboxID) error
 	MessagesCreated([]imap.Message, [][]byte, [][]imap.MailboxID) error
 	MessageUpdated(imap.Message, []byte, []imap.MailboxID) error
@@ -137,6 +139,10 @@ func (s *testSession) mailboxCreated(user string, name []string, withData ...str
 	return s.mailboxCreatedWithAttributes(user, name, defaultAttributes, withData...)
 }
 
+func (s *testSession) setAllowMessageCreateWithUnknownMailboxID(user string, value bool) {
+	s.conns[s.userIDs[user]].SetAllowMessageCreateWithUnknownMailboxID(value)
+}
+
 func (s *testSession) mailboxDeleted(user string, id imap.MailboxID) {
 	require.NoError(s.tb, s.conns[s.userIDs[user]].MailboxDeleted(id))
 }
@@ -199,6 +205,24 @@ func (s *testSession) mailboxCreatedCustom(user string, name []string, flags, pe
 	return mboxID
 }
 
+func (s *testSession) messageCreatedWithMailboxes(user string, mailboxIDs []imap.MailboxID, literal []byte, internalDate time.Time, flags ...string) imap.MessageID {
+	messageID := imap.MessageID(utils.NewRandomMessageID())
+
+	require.NoError(s.tb, s.conns[s.userIDs[user]].MessageCreated(
+		imap.Message{
+			ID:    messageID,
+			Flags: imap.NewFlagSetFromSlice(flags),
+			Date:  internalDate,
+		},
+		literal,
+		mailboxIDs,
+	))
+
+	s.conns[s.userIDs[user]].Flush()
+
+	return messageID
+}
+
 func (s *testSession) messageCreated(user string, mailboxID imap.MailboxID, literal []byte, internalDate time.Time, flags ...string) imap.MessageID {
 	messageID := imap.MessageID(utils.NewRandomMessageID())
 
diff --git a/tests/updates_test.go b/tests/updates_test.go
index a32f7293..36d05846 100644
--- a/tests/updates_test.go
+++ b/tests/updates_test.go
@@ -1,7 +1,10 @@
 package tests
 
 import (
+	"github.com/emersion/go-imap/client"
+	"github.com/stretchr/testify/require"
 	"testing"
+	"time"
 
 	"github.com/ProtonMail/gluon/imap"
 	"github.com/ProtonMail/gluon/internal/utils"
@@ -306,3 +309,24 @@ func TestBatchMessageAddedWithMultipleFlags(t *testing.T) {
 		s.flush("user")
 	})
 }
+
+func TestMessageCreatedWithIgnoreMissingMailbox(t *testing.T) {
+	runOneToOneTestClientWithAuth(t, defaultServerOptions(t), func(c *client.Client, s *testSession) {
+		mailboxID := s.mailboxCreated("user", []string{"mbox"})
+		{
+			// First round fails as a missing mailbox is not allowed.
+			s.messageCreatedWithMailboxes("user", []imap.MailboxID{mailboxID, "THIS MAILBOX DOES NOT EXISTS"}, []byte("To: Test"), time.Now())
+			status, err := c.Select("mbox", false)
+			require.NoError(t, err)
+			require.Equal(t, status.Messages, uint32(0))
+		}
+		{
+			// Second round succeeds as we publish an update that is allowed to fail.
+			s.setAllowMessageCreateWithUnknownMailboxID("user", true)
+			s.messageCreatedWithMailboxes("user", []imap.MailboxID{mailboxID, "THIS MAILBOX DOES NOT EXISTS"}, []byte("To: Test"), time.Now())
+			status, err := c.Select("mbox", false)
+			require.NoError(t, err)
+			require.Equal(t, status.Messages, uint32(1))
+		}
+	})
+}