Split from this thread.
I am having the same problem that Mike is having, but in reverse - for two days, mail in my default account has loaded to the Windows Live Mail platform, but none from my secondary account. Both are Hotmail accounts that I have had for over 10 years. Passwords are correctly entered in WLM, and I am receiving no errors when checking for or sending mail; I simply get "No new email" at the bottom of the window. When I access the secondary account directly via Hotmail.com/Outlook.com, all my emails from the last two days are there. I have even tried updating WLM while looking at my inbox in my web browser, and WLM still says there are no new messages.
I am running WLM 2011 on Windows Vista, and it has worked with no problems for several years. I have made no changes to the setup recently.