Can't set up IMAP email account
I want to set up a new IMAP account in Mail on my iMac. I had no problem doing this on the Mac Mini, Mac Air or iPhone. When attempting the setup on the iMac, there seems not to be an option to select the email account type (i.e. POP3, IMAP or Exchange), as there was on the other devices. Instead, after entering the Full Name, Email Address and Password into the Add Account box, Mail searches for the account, connects to the mail server and adds it as an Exchange account, bypassing the setup steps for each of the incoming and outgoing servers. How can I overcome this and set the account up as IMAP?
iMac (21.5-inch Mid 2010), iOS 6.0.1