IMAP's IDLE function is supported by a wide range of email clients. This feature establishes a connection with the mail server, so if a new email arrives, it notifies the mail client and sends the message to the client.
Processes like the ones on your site often open for a very little period of time before closing. We advise removing this function since it keeps the process running constantly and may cause your account to exceed its resource limits. The following is the procedure for the most widely used mail clients:
From the Mail drop-down, click on Preferences
Navigate to Accounts
Select your IMAP account from the list
Click on the Advanced tab and disable the Use Idle setting
*Please note that this option has been completely removed after OSX Yosemite
Access Tools, then navigate to Send/Receive
Click on Send/Receive Settings
Select Define Send/Receive Groups
For each Group, Uncheck: Schedule an automatic send/receive every x minutes
Click Close.
Go to the Send/Receive tab
Select Send/Receive Groups and click on Define Send/Receive Groups;
For each Group shown, Uncheck: Schedule an automatic send/receive every x minutes
Click Close.
Select your IMAP Email Account
Select More - Settings - Account Settings
Change Folder poll check frequency to Never.