diff --git a/src/engine/imap/transport/imap-deserializer.vala b/src/engine/imap/transport/imap-deserializer.vala
index 559a5e78..90c83549 100644
--- a/src/engine/imap/transport/imap-deserializer.vala
+++ b/src/engine/imap/transport/imap-deserializer.vala
@@ -562,6 +562,12 @@ public class Geary.Imap.Deserializer : BaseObject, Logging.Source {
         char ch = *((char *) user);
         switch (ch) {
             case '[':
+                // "[" is a valid character for flags (and used by Gmail)
+                if (this.is_parsing_flags) {
+                    append_to_string(ch);
+                    return State.FLAG;
+                }
+
                 // open response code
                 ResponseCode response_code = new ResponseCode();
                 push(response_code);
diff --git a/test/engine/imap/transport/imap-deserializer-test.vala b/test/engine/imap/transport/imap-deserializer-test.vala
index e5e642df..b4f62305 100644
--- a/test/engine/imap/transport/imap-deserializer-test.vala
+++ b/test/engine/imap/transport/imap-deserializer-test.vala
@@ -273,7 +273,7 @@ class Geary.Imap.DeserializerTest : TestCase {
     public void gmail_broken_flags() throws GLib.Error {
         // As of 2020-05-01, GMail does not correctly quote email
         // flags. See #746
-        string flags = """* FLAGS (\Answered \Flagged \Draft \Deleted \Seen $Forwarded $MDNSent $NotPhishing $Phishing Junk LoadRemoteImages NonJunk OIB-Seen-INBOX OIB-Seen-Unsubscribe OIB-Seen-[Gmail]/Important OIB-Seen-[Gmail]/Spam OIB-Seen-[Gmail]/Tous les messages)""";
+        string flags = """* FLAGS (\Answered \Flagged \Draft \Deleted \Seen $Forwarded $MDNSent $NotPhishing $Phishing Junk LoadRemoteImages NonJunk OIB-Seen-INBOX OIB-Seen-Unsubscribe [GMail]/Sent_Mail OIB-Seen-[Gmail]/Important OIB-Seen-[Gmail]/Spam OIB-Seen-[Gmail]/Tous les messages)""";
         this.stream.add_data(flags.data);
         this.stream.add_data(EOL.data);
         this.deser.quirks = new Imap.Quirks();