The IDLE function (known as IMAP push) is used by almost every mail client.
It allows the IMAP email users to receive any email changes without refreshing their mailbox.
In some cases, however, the email client stalls and keeps opening multiple processes that cannot be closed.
Disabling the IDLE processes on your mail client will prevent these processes from piling up.
Here are the steps how you can do this for some of the most popular mail clients,
Mozilla Thunderbird
Go to Tools
Select Account Settings
Select Server Settings
Uncheck the Allow immediate server notifications when new messages arrive
MacMail (up to OS X El Capitan)
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
NB: This configuration option has been removed from the MacMail client in the macOS versions newer than El Capitan.
Microsoft Outlook 2010
Go to the Send/Receive tab
Select Send/Receive Groups and click on Define Send/Receive Groups
For each Group, Uncheck, Schedule an automatic send/receive every x minutes
Click Close button
Microsoft Outlook 2007
Access Tools and 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 button
Outlook for Mac
Click Outlook
Select Preferences
Then Accounts
Choose an email account
Click Advanced
Make sure that Use IMAP IDLE (if the server supports it) is not checked
Click OK to save the changes
Apple iPad
Go to Settings and select Mail, Contacts, Calendars
Under Accounts click Fetch New Data
Turn ON Push and make sure it is set to Manually
Android Mail
Select your IMAP account
Go to Menu | More | Settings | Send & Receive
Select Set download frequency
Change Peak times and Off-peak times to Manual
Android K9 Mail
Access your IMAP email account
Go to Menu | More | Settings | Account Settings
Change Folder poll check frequency to Never
Palm WebOS
Select Preferences & Accounts from the application menu (top Email tab)
Under Accounts, select your account
Scroll down to the box titled Sync
Change the setting for Get Email to As items arrive
Use the back gesture to save your configuration