We're evaluating Zimbra with the Zimbra Network Edition, and I've recently upgraded from v5 to v6. What I did to upgrade was to backup all emails, remove Zimbra 5, then install Zimbra 6, restore user data. I didn't need to do it this way but I thought that testing the disaster recovery would be good before going live with the product.
After the install of Zimbra 6, we've noticed that those using Zimbra are finding it very slow to send email. Calendar, receive email, contacts are all fine. Any Ideas what could be wrong?