I am running a Windows 7 Pro 64Bit computer using Outlook 2010 as my mail client. Some time ago, my Service Provider switched my mail system from POP to IMAP. To do this a new email address was created with a (1) at the end. Now the original email address without the suffix (1) still shows in my list of folders, however, when I go into Account Settings it does not appear as an account. The majority of my emails appear in the Inbox for the address with the suffix (1) but strangely I will get the occasional email in the Inbox without the suffix.
Just to muddle things up I decided recently that I didn’t like IMAP because everything was slower so I decided to switch back to POP (I don’t need synchronised emails).
I didn't find the right solution from the internet.