I have 4 emails accounts in my config and if one of them is not ticked to check for emails on startup then none of them are checking for emails on start up. It works fine if all are ticked to check on startup in the "Retrieval Options". This seems to be the same as Bug 317072 that was closed as "works for me", I have had this problem for a while and only found the "solution" by accident on this one user account out of 3 other users accounts on this machine that work that work fine as they are all ticked.
Seems to work now