Reporting bugs
calibre is a very rapidly evolving piece of software, with weekly releases. As a results bugs are inevitable. We rely on calibre's users to report these bugs, so that they can be fixed as quickly as possible. To report bugs you will have to register for a free account at the calibre bug tracker and then open a new ticket with your bug/enhancement report.
Before opening a new ticket, please run a quick search of existing tickets, to make sure there isn't already an open ticket about your issue. When reporting bugs please include as much information as possible, as that makes it easier for us to identify the source of the problem. Remember that calibre is developed by volunteers in their spare time, so by taking these steps, you are helping to ensure that as much of that time as possible is spent actually coding as opposed to doing administrative tasks like closing duplicate bug reports.
You can also use the ticket system to request new features. To mark a ticket as a request for a new feature, change its type to "Enhancement".