To quickly mark all messages read for a certain time period, or for “all time” — highlight the “date” that you want to mark all items “read/opened” for..press your menu key… select “Mark Prior Opened”

To mark all your messages as opened/read, from anywhere within your mailbox, press “T” to get to the top — press Menu – Select “Mark Prior Opened”.

Use with caution however, as the option to “Delete Prior” is right below the mark prior opened menu option — Be aware that if you select delete prior in error, you may not be able to get those messages back on your device unless you performed a very recent backup.  On the plus side.. you will still have them in your Outlook or Lotus Notes mailbox so all is not lost!

Marking all messages as open is useful when you are returning from vacation and when the blackberry is powered back on, 2000+ unread messages start to trickle through!