In future Cpanel updates, /etc/cpanel_exim_system_filter may get overwritten if you edit it.
Solution:

1. cp /etc/cpanel_exim_system_filter /etc/cpanel_exim_system_filter_custom
2. Then edit /etc/cpanel_exim_system_filter_custom and remove the eml| from the four non-commented lines that reference it. You can also do this for URL, and LNK
3. Then log into WHM, click on Exim Configuration Editor, and change the system filter at the bottom from /etc/cpanel_exim_system_filter to /etc/cpanel_exim_system_filter_custom
4. Save the changes

Now Cpanel will use /etc/cpanel_exim_system_filter_custom, which if properly edited to remove the ’eml|’ references in the particular lines will allow EML attachments to go through in the future

I often have to look over CPanel log files, and sometimes it just slips my mine on where they are located and what is contained in each one of them. Thought I would put together a listing of the files/locations and what is contained in them. Hope others find this useful.
CPanel stores it’s log files in the /usr/local/cpanel/logs directory. Below is a list of the common log files that are located in a cPanel server along with a short description.

access_log — cPanel access log for both cPanel and WHM
error_log — cPanel error log
license_log — cPanel license log
login_log — cPanel user login log
melange.log — cPanel chat server log
melange_msg.log — cPanel chat server message log
stats_log — cPanel web stats log

Also cPanel keeps other system logs in the /var/log/ directory.

bandwidth — cPanel total bandwidth logs for the entire server
chkservd.log — chkservd service log
clamav — clamav log directory
cpupdate.log — cPanel update log
exim_mainlog — Exim email transaction log
exim_paniclog — Exim error log
exim_rejectlog — Exim rejected email log
maillog — Transaction and login log for all mail services
pgsql — PostgreSQL log file

cPanel keeps the domain weblogs in the /usr/local/cpanel/domlogs directory for each domain name that is hosted on the server. This includes FTP transfer logs for each account.