I'm planning on upgrading our Zimbra 4.5.8 FOSS installation to 5.0.1 during this coming weekend. We have what I consider a pretty large mail store (~135 GB). As far as I know we have no major issues with our current installation. Based on what I've read in these forums I'm expecting a rather lengthy upgrade process (several hours). So, my question is when the "database integrity" prompt comes up during the upgrade process should I answer "Y" or "N"? I'm assuming that based on my mail store size the check could add significant time to the upgrade process. What is the risk in skipping the check? If there are existing problems with my database they are not presenting themselves in any noticeable ways now. Does skipping the check just mean that any problems would continue to exist, or does it increase the chances of the entire upgrade process failing, or is the database going to be "fixed" anyway due to the version change?