I'm downloading my email to a private Gmail account, from another POP3 server (SmarterMail Server 4.3). In Gmail I'm getting the error:
Error: Too many messages to download. Server returned error "There are too many messages on the other server. Please delete some mail from..."
So I can reduce the number of emails, but I don't know what maximum count I'm trying to hit.
Also using google on the error message only returns a few results from google sites, but non refer to an email count that would cause this error to start showing.