I’m running version 4.6.744 on Windows 2000. In this version Internet Mail Provider does NOT starts automatically at Windows start-up. There is a message “waiting a subsystem to start” which lasts for ever… I’ve sorted out it by MANUAL terminating the Internet Mail Provider and restarting it again.
Earlier versions had sometimes this problem but less than often. In the last version it is a persistent problem! And it’s a little annoying 
What is your email program?
The message “waiting a subsystem to start” is usually associated with Outlook/Exchange plug-in is waiting for MS Outlook (not outlook express) or MS Exchange email client to start. If you aren’t using MS Outlook or Exchange you don’t need this plug-in enabled. The problem/message is resolved by starting MS Outlook.
My mail client is Mozilla Thunderbird. But I’m not sure it’s so for the client. There must be some inconsistency in the settings within the Avast mail provider. That’s why I’m posting that issue… ???
If you have both the Internet Mail provider (correct one for thunderbird) and Outlook/Exchange (for MS Outlook/Exchange only) also enabled it is the one that causes the “waiting for subsystem to start” message. It will be waiting for a non-existant email client, MS Outlook/Exchange to start, ensure the Outlook/Exchange provider is terminated.