[quote user="Brian Fluet"]... A known solution is to use the Pegasus Mail Notsplit utility to generate message files from the .PMM for re-integration back into Pegasus Mail folders but what could the approach be when Pegasus Mail is not in the picture? An obvious answer of placing the .cnm files into a mailbox directory isn't practical when there's hundreds if not thousands of them.[/quote]
I believe in that case you've got a problem. Also in case your server (where Mercury is running) or your accessing client is a 64bit system, any IMAP client wouldn't access the mailbox directly but always via the 32bit Mercury-I. And 32bit software can address max 2GB of RAM (except some special cases of 32 bit software which is able to address up to 4 GB). Don't know whether other (64bit) IMAP server are able to access Mercury/Pmail mailboxes? Maybe someone has tested it already?
I regularly check the mailboxes of my users and carry out a search for files larger than 1 GB. If I find something, the user get a message to remove big attachments or to create a new mail folder to avoid a further increasing.