Our users are on Win7, Outlook 2010 and we use Exchange 2003 (soon to upgrade to 2008 R2). Ever since moving to Outlook 2010, a number of users have experienced an issue where they compose an email, hit the Send button, but nothing happens. I have managed to track the problem to an issue with the address saved in the user's autocomplete file. If you remove the address from the file, and type it in again manually, the email will then send. The autocomplete files were all imported from the user's 2003 Outlook NK2 file.
Anyone come across this problem before, and hence, a fix for it? Despite much googling, I have been unable to word my problem in such a way that I can find anyone else with the same issue.