I am using exchange 2016, its Mail.queue is located on C drive it is continously increasing due to which some times fail flow stopped and after restarting exchange services, it works. Current size is more than 14 GB. I have some of client who are using exchange 2010 and exchange 13, their mail.queue never increase while they have many mailboxes than this. I decreased Safety net time and other thing but stilll increasing. I followed below links.
Every time, Recreating Mail.queue is not possible for.