If they “recycle” backups, then they aren’t used to retain email long term. If they didn’t restore her system after the crash, then they aren’t for restoring systems either. What exactly are the backups for? Someones lying.
It’s entirely likely that tape backups were recycled ,, if they were used for incremental backups , however there are the full backups usually taken in weekly or monthly intervals that you generally restore from first and THEN apply the changes/updates from the incrementals..
The docs exist or were intentionally destroyed ,, and their destruction would have entailed the loss or spoilage of tens of thousands of other employees backups also.
Here’s the deal with the excuse of tapes being written over every six months. What happens. The tapes are loaded with data. Sent offsite. The offsite company copies from tape to their hard drives (virtual tapes). And the tapes are sent back to the company (IRS) and go into a tape library for restores, disaster recovery etc. After a certain period of time (6 months - 2 years) the tapes go back into production and are written over. But there is still a copy at the offsite facility on a virtual library.