diff --git a/lib/mailbox-handler.js b/lib/mailbox-handler.js
index 4fff3bd7..355c4921 100644
--- a/lib/mailbox-handler.js
+++ b/lib/mailbox-handler.js
@@ -95,6 +95,9 @@ class MailboxHandler {
             if (!mailboxData) {
                 return callback(null, 'NONEXISTENT');
             }
+            if (mailboxData.path === 'INBOX') {
+                return callback(null, 'CANNOT');
+            }
             this.database.collection('mailboxes').findOne({
                 user: mailboxData.user,
                 path: newname