I’ve been having some “odd” email problems since installing Vista. One of my email accounts (Telus) fails (times out) with an error 0x800CCC19 whenever there is an email in my inbox longer than about one or two kilobytes. If I use my email service’s web interface and delete any such messages, the connection works fine.
I tried the obvious things, such as disabling my anti-virus program and increasing the time out value in Windows Mail. I then launched my trusty Google search, and found this forum thread on the topic. The thread included the usual advice, but one post stood out:
Jake (Msg. 5) Posted: Tue Feb 06, 2007 4:03 pm
Post subject: Re: Receiving Mail [Login to view extended thread Info.]
There is a fix floating around that goes like this.
This is very step-by-step, so bear with me.
1. Go to the Vista start menu and type cmd
2. The search results will display a program titled cmd
3. Right-click on the link and select “Run as administrator”
4. type “netsh interface tcp set global autotuning=disabled” without the
5. Test your POP account and see if you can now download the files.
6. If nothing changes, reenable the autotuning feature by typing “netsh
I followed the instructions exactly, and voila- email worked! I’ll have to do some more research later on what “global autotuning” does, and why it is causing my email session to fail. Thanks, “Jake”, whoever you are!
UPDATE: I found a good description of what Vista’s “autotuning” is about, and why it might be causing problems. Basically, autotuning is a negotiation between the client and the server regarding network packet size, and the problem arises when the process agrees to a large packet size but where some part of the negotiation gets blocked by an intermediate router/network device. Apparently, turning it off doesn’t have a significant performance impact in most situations. Now I’ll have to investigate my router to see if it might be causing problems with the negotiation….