diff --git a/imap.js b/imap.js
index 148bfcce..0f0a771f 100644
--- a/imap.js
+++ b/imap.js
@@ -1003,12 +1003,16 @@ server.onCopy = function (path, update, session, callback) {
                         uidNext: true
                     }, (err, item) => {
                         if (err) {
-                            return updateQuota(() => callback(err));
+                            return cursor.close(() => {
+                                updateQuota(() => callback(err));
+                            });
                         }
 
                         if (!item || !item.value) {
                             // was not able to acquire a lock
-                            return updateQuota(() => callback(null, 'TRYCREATE'));
+                            return cursor.close(() => {
+                                updateQuota(() => callback(null, 'TRYCREATE'));
+                            });
                         }
 
                         let uidNext = item.value.uidNext;
@@ -1029,7 +1033,9 @@ server.onCopy = function (path, update, session, callback) {
 
                         db.database.collection('messages').insertOne(message, err => {
                             if (err) {
-                                return updateQuota(() => callback(err));
+                                return cursor.close(() => {
+                                    updateQuota(() => callback(err));
+                                });
                             }
 
                             copiedMessages++;
diff --git a/lib/message-handler.js b/lib/message-handler.js
index 18f6b7be..d4ddf8ce 100644
--- a/lib/message-handler.js
+++ b/lib/message-handler.js
@@ -611,11 +611,11 @@ class MessageHandler {
                                 uidNext: true
                             }, (err, item) => {
                                 if (err) {
-                                    return done(err);
+                                    return cursor.close(() => done(err));
                                 }
 
                                 if (!item || !item.value) {
-                                    return done(new Error('Mailbox disappeared'));
+                                    return cursor.close(() => done(new Error('Mailbox disappeared')));
                                 }
 
                                 let uidNext = item.value.uidNext;
@@ -647,7 +647,7 @@ class MessageHandler {
                                     _id: message._id
                                 }, updateOptions, err => {
                                     if (err) {
-                                        return done(err);
+                                        return cursor.close(() => done(err));
                                     }
 
                                     if (options.session) {