All,
We've long been fans of the open source Outlook Plugin CalDAVSynchronizer. It's a great way to sync BOTH your SmarterMail calendars and contacts with Outlook using WebDAV. However, there were some occasional issues that we noticed and that were reported to us by our customers.
We were able to troubleshoot those issues and get the necessary info (sync logs, etc.) over to the developers of the plugin. They notified us today that they released a hot fix that resolves all of the issues we reported. Realize these weren't SmarterMail issues, which is why we reached out to the team at CalDAVSynchronizer and asked for their assistance.