Wasted

Hi

In Storage folders/Recovered items I've just noticed a lot of folders, each
named as a date (from yesterday, going back 2 months, with varying gaps
between dates), and under each of those are subfolders containing old
messages.

What are these messages recovered from? Does it indicate something is
failing? I've had no problems with my computer (Vista 64bit)

Can I just delete these subfolders?

Thanks