No one can explained what was being backed upped and how. .PST files are stored in the main My Documents folder now where everything typically is located. You backup your My Document folder, you back up Outlook. But my main point was, “If the backup existed for three months on tapes, why weren’t they restored the next day or so?” That is why you back up.
The user would need to complain of any missing emails before IT staff would attempt to find them. Exchange backups were only held for 6 months and then recycled according to some accounts. If those reports are accurate, then at best they would have been able to get a snap shop of her mailboxes back to Jan 2011 or there about. The retention policy didn't change until the IG investigation got underway.
http://freerepublic.com/focus/f-news/3170845/posts?page=61#61
click on the ways and means committee link and scroll down to page 9 for IRS email policy explanation.