It typed the above search terms in google, and the first page had several hits like yours:
The last link notes that it happens if Outlook receives an email. Sending and receiving at the same time seems to be too much. So maybe you can disable the receiving while doing it.
I can't find anything relating to this problem on the MSKB. So it's time to tell them. Just phone. If it's a problem in their software (and it seems to be, from all that discussions) it's free. And if y9u happen to have corporate support it's included.
Using Office 2007 to create an email mailmerge using a list about 1,400 emails in Excel.
After I finished the merge and send the emails a few messages are generated in Outlook before Word begins to hang and stop responding. The amount of email messages that are generated are random. Sometimes it could be anywhere from 2 to 500. I have been able to generate all emails a few times. I have done anything from making sure cell format in Excel is correct, convert files as 2003 version, making sure I have all updates, and I have even cut the email list shorter. Is there a fix out there or is there something that I am missing?
If I do this in Office 2003 it works fine. My current version of Word is (12.0.6213.5000) SP1 MSO (12.0.6213.1000). I'm using Windows XP Pro SP 2 with latest updates if that helps.