diff --git a/app/src/main/java/eu/faircode/email/AdapterMessage.java b/app/src/main/java/eu/faircode/email/AdapterMessage.java
index 549235afe7..a40e096973 100644
--- a/app/src/main/java/eu/faircode/email/AdapterMessage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterMessage.java
@@ -2894,7 +2894,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                                         (EntityMessage.SMIME_SIGNENCRYPT.equals(message.ui_encrypt) &&
                                                 !EntityMessage.SMIME_SIGNENCRYPT.equals(message.encrypt));
                         if (lock)
-                            onMenuResync(message);
+                            onActionLock(message);
                         else
                             onActionDecrypt(message, false);
                         break;
@@ -3799,6 +3799,46 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                             .putExtra("type", encrypt));
         }
 
+        private void onActionLock(TupleMessageEx message) {
+            Bundle args = new Bundle();
+            args.putLong("id", message.id);
+
+            new SimpleTask<Void>() {
+                @Override
+                protected Void onExecute(Context context, Bundle args) throws Throwable {
+                    long id = args.getLong("id");
+
+                    DB db = DB.getInstance(context);
+                    try {
+                        db.beginTransaction();
+
+                        EntityMessage message = db.message().getMessage(id);
+                        if (message == null)
+                            return null;
+
+                        File file = message.getFile(context);
+                        Helper.writeText(file, null);
+                        db.message().setMessageContent(message.id, true, null, null, null, null);
+                        //db.message().setMessageSubject(id, subject);
+                        db.attachment().deleteAttachments(message.id);
+                        db.message().setMessageEncrypt(message.id, message.ui_encrypt);
+                        db.message().setMessageStored(message.id, new Date().getTime());
+
+                        db.setTransactionSuccessful();
+                    } finally {
+                        db.endTransaction();
+                    }
+
+                    return null;
+                }
+
+                @Override
+                protected void onException(Bundle args, Throwable ex) {
+                    Log.unexpectedError(parentFragment.getParentFragmentManager(), ex);
+                }
+            }.execute(context, owner, args, "message:lock");
+        }
+
         private void onActionAnswer(TupleMessageEx message, View anchor) {
             properties.reply(message, getSelectedText(), anchor);
         }
diff --git a/app/src/main/java/eu/faircode/email/DaoAttachment.java b/app/src/main/java/eu/faircode/email/DaoAttachment.java
index 288ef3671f..935c663413 100644
--- a/app/src/main/java/eu/faircode/email/DaoAttachment.java
+++ b/app/src/main/java/eu/faircode/email/DaoAttachment.java
@@ -123,6 +123,7 @@ public interface DaoAttachment {
     int deleteAttachment(long id);
 
     @Query("DELETE FROM attachment" +
-            " WHERE message = :message")
+            " WHERE message = :message" +
+            " AND encryption IS NULL")
     int deleteAttachments(long message);
 }