I have Exchange 2007 and Outlook 2007 in a Windows 2008 domain. About a week ago, I started getting complaints that meeting reminders were not working for some users. I have tried the /cleanreminders and the /cleanfreebusy commands, but neither worked. I moved the mailbox from one server to a second server and the reminders started working. About 2 days later they stopped working again for the same user. When I try OWA, the reminders work.
The only thing that has really changed in my environment, is that I have added a 3rd Exchange 2010 server into the mix, but that was about a month ago and this problem never appeared until about a week ago.