Before you create a new post a bug, we'd appreciate if you first check GitHub and this forum to see if your issue has been reported already:
- GitHub issues marked with the Bug label
- The Bug Reports category on our forum (you're already here)
If it doesn't seem like your bug has already been reported, then please go ahead and create a new post, but make sure to include the following information. If you don't, this will be the first thing we ask you for. 
- Your browser and its version: (e.x. Chrome 52.1, Firefox 48.0, IE 10)
- Your operating system: (e.x. OS X 10, Windows XP, etc)
- The type of database(s) you've connected to Metabase: (e.x. MySQL, Postgres, MongoDB, …)
- The version of Metabase you're running: (e.x. 0.29.3)
- Metabase hosting environment: (e.x. Docker, AWS EB, the Mac app, Heroku, Linux/Ubuntu 12, etc.)
- Metabase's internal database type: (H2 is the default)
- Repeatable steps to reproduce the issue, and any relevant error messages in the JavaScript developer's console in your web browser, or in the server logs.