Has there ever been another version of Outlook installed on this computer?
If so, recreate your mail profile;
http://www.howto-outlook.com/faq/newprofile.htm
Adding an extra mail profile to see if the issue goes away wouldn't hurt
either.
Are these POP3 accounts on the same server? In that case, increase the
send/receive interval. You're currently on the edge of things already when
it comes to send/receive settings.

Signature
Robert Sparnaaij [MVP-Outlook]
Coauthor, Configuring Microsoft Outlook 2003
http://www.howto-outlook.com/
Outlook FAQ, HowTo, Downloads, Add-Ins and more
http://www.msoutlook.info/
Real World Questions, Real World Answers
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> I have Googled for days and read every thread with the message in my
> subject
[quoted text clipped - 26 lines]
> Anti-Virus: Uninstalled it and spyware detection for the purpose of
> diagnosing this problem.
Sandy E - 10 Mar 2008 18:41 GMT
I recreated my profile and upped the send/receive to 10 minutes. I also took
3 email accounts and forwarded them all to one account. So, I'm left with 2
send/receive groups each with one account in them.
I forgot to mention that I have run scanpst on all my pst files.
After recreating the profile, things seem ok for now, but I've read in
previous posts that people have started having trouble again soon after. I'll
update here if I do.
One problem that hasn't gone away - when I used Outlook 2003 (I imported my
2003 pst's into 2007), I could download 200 messages in a matter of 5
seconds. Now, with 2007, I can download 200 messages in a matter of 5
minutes. I get a large volume of mail, so this is dissapointing. I wonder why
2007 downloads mail so much slower.
> Has there ever been another version of Outlook installed on this computer?
> If so, recreate your mail profile;
[quoted text clipped - 36 lines]
> > Anti-Virus: Uninstalled it and spyware detection for the purpose of
> > diagnosing this problem.
Sandy E - 10 Mar 2008 19:09 GMT
Update - Outlook is back to synchronizing folders again, so I am left with
the same problem as before. Also, there has never been a different version of
Outlook on this machine. I imported a couple 2003 PSTs into the fresh install
of 2007 on the machine, but it's the only version that's ever been installed.
> I recreated my profile and upped the send/receive to 10 minutes. I also took
> 3 email accounts and forwarded them all to one account. So, I'm left with 2
[quoted text clipped - 52 lines]
> > > Anti-Virus: Uninstalled it and spyware detection for the purpose of
> > > diagnosing this problem.
Sandy E - 11 Mar 2008 00:19 GMT
This is still a major problem and would REALLY appreciate any help. Even if
someone could point me to a paid service that could help me find a solution.
> Update - Outlook is back to synchronizing folders again, so I am left with
> the same problem as before. Also, there has never been a different version of
[quoted text clipped - 57 lines]
> > > > Anti-Virus: Uninstalled it and spyware detection for the purpose of
> > > > diagnosing this problem.
Darrell - 13 Mar 2008 00:42 GMT
I'm having the exact same issue as Sandy E.
Anybody? Bueller?
I've tried repairing, uninstalling and re-installing, disabling firewall,
symantec endpoint...
> This is still a major problem and would REALLY appreciate any help. Even if
> someone could point me to a paid service that could help me find a solution.
[quoted text clipped - 60 lines]
> > > > > Anti-Virus: Uninstalled it and spyware detection for the purpose of
> > > > > diagnosing this problem.