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Don't forget afterwards that you need to go to Mailbox-> Erase Deleted Items-> In All Accounts... to actually delete the emails and free up your email quota.
In OWA:
On a 2 button mouse, Left CLICK
OR
On a 1 button mouse, Control-CLICK
on "Deleted Items" and select "Empty Folder" to dump all of your deleted items.
Then after you've erased deleted items in all your accounts, you can set your email back to view your emails by date.
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