Emails look to be downloading but don't show up in the New Mail box

When I check an email account I may see a message indicating that "1 or 2 of 5 messages are downloading but then either just some or none of them show up in my New Mail folder. I have no filters - that I know of....on an earlier instrallation I would get all, say 5, messages but one or two would go to a Junk Mail folder...nothing goes to Junk or Spam....:-((