Why is MS Outlook Synchronizing Folders? How do I stop it?

[david.f.jenkins]

Is there a maximum size for files that can be sent as e-mail
attachments out of Outlook?

I am having great difficulty sending a large (12MB) file as an e-mail
attachment. When I send it to one recipient (to whom I can
successfully send smaller files all day long), for instance, it bounces
with a 503 Authentication Error. If I send it to my wife (across the
room; same ISP, different system), I get an 0x800ccc0f error in OL:
"Connection to Server Interrupted". This has happened with several
diffeent files, so I doubt it's the file contents (which are PowerPoint
files, BTW) that's causing the problems.

In troubleshooting this, I notice that every time I send mail (and
maybe receive - don't know about that) I have an icon in the system
tray that says "Microsoft Outlook is Synchronizing Folders".
Everything then seems to slow to a crawl.

I am XP Pro SP2 with Office 2003. I don't (consciously) do any offline
processing, and I have no .ost files on my hard disk.

What is being synchronized? How do I stop that from occurring? I see
that there have been many, many posts regarding this problem, but no
MVP seems to take the time to explain what's happening to cause it, how
it might have been started, and how to make it quit, what the
ramifications are of synchronizing or not synchronizing etc.

The only thing that I've changed recently is that I added a new mail
account. Thinking that I may have inadvertently caused OL to go south,
I have since deleted that account, but the icon still appears. And I
still can't send this big file.

Can anyone help?

 

[Dave Jenkins]

As an update:

I have turned off automatic send/receive, and am still getting errors when I
send but a 2MB file. I can successfully send a much smaller file (200kB),
however. Whatever the rpoblem is, it seems to be filesize-sensitive.

 

[david.f.jenkins]

Here is more info that may be pertinent. My wife uses the same ISP,
and the same mail server. She is able (from another PC) to send large
files to me, but I am unable to send them to her. When she sends the
file, she also gets the Synchronizing Folders icon, and the Send seems
to take quite a fairly long time (4 minutes for a 2MB file - it should
go a lot faster than that at 500kbps).

So there's probably something wrong with the way my system's running -
where do I look? My personal folders total about 300MB - is that
dangerously high? What else should I check?

 

[Dave Jenkins]

Here's another bit of information: I have a hugely complex set of personal
folders set up, with thousands (maybe) of messages stored. I renamed the
current .pst and had Outlook start with new one, in the hopes that the
compexity of the old folder structure might be contributing to the problem.
No soap. Still getting "interrupted" during the transfer of larger
attachments.

 

[david.f.jenkins]

I think the Oultook considerations were a red herring in this case.
Just to wrap this up and close it out: the Tcp settings were probably
not set optimally on this pc. In particular, SackOpts = 0 was set
(changed to 1) and TcpMaxDataTransmissions was set to 1 (changed to
(default)).

With those changes (and perhaps, under goading, my ISP tweaked his
radio), I've been able to send these files without problem for the last
72 hours.