I have a yahoo and gmail account.  Most of my e-mail is on yahoo. When using windows live, I keep getting this message

Unable to send or receive messages for the Sbcglobal IMAP account. Header download for the 'Randy Netz' folder did not complete. Could not update cached message flags with IMAP server.

Server Response: The server did not respond to this IMAP command before the connection was terminated.
Server: 'imap.mail.yahoo.com'
Windows Live Mail Error ID: 0x800CCC0F
Protocol: IMAP
Port: 993
Secure(SSL): Yes

It is not always the same folder that doesn't complete.

I have several other problems as well.

I receive error messages that say that the server timed out before the messages were updated.  It suggests that I have a lack of memory even though I have plenty. 

some of my messages get lost altogether

Some sent messages are moved to my junk folder instead of my sent folder

Please advise.