When Hiri is first launched and connected to your email, it starts synchronizing (downloading) the last 3 months worth of your emails and tasks. All the downloaded emails are stored on your computer. Hiri doesn't sync all the emails in your account because that would take too long and most of the time you don't need to have all of your emails stored on your computer.
If you wish to download more email, you can always tweak the synchronization range by going to Settings -> Account and dragging the slider. You can choose one of:
- 3 months (default)
- 6 months
- 1 year
- 2 years
Note that this doesn't affect the calendar, since it isn't downloaded. The calendar works in online mode only - it requires a working internet connection.