I've got courier-imap 4.6.0-2.1ubuntu1 running on Ubuntu 10.04.4 LTS on a virtual/cloud LAMP machine with 1GB RAM.
There is a particular (unmaintained) email address which has 100,000+ emails, all in the INBOX, and for a few weeks now I've been unable to open the mailbox in Roundcube webmail client (it gives a "can't allocate memory" error message) or Mozilla Thunderbird (silent failure).
I've just tried using mutt to read the mailbox, and I get the same "can't allocate memory" error message.
What can I do to resolve the problem so I can clean up the mailbox and reduce the number of emails in the INBOX? Can I just move some of the files around?
This is the directory listing of the Maildir:
total 73060
drwx------ 2 vmail vmail 4096 2013-11-06 15:43 courierimapkeywords
-rw-r--r-- 1 vmail vmail 20676660 2014-02-25 10:32 courierimapuiddb
drwx------ 2 vmail vmail 31870976 2014-02-25 10:32 cur
-rw-r----- 1 vmail vmail 2393 2014-02-25 10:38 maildirsize
drwx------ 2 vmail vmail 1482752 2014-02-25 10:38 new
drwx------ 2 vmail vmail 4096 2014-02-25 10:38 tmp