Hi Terrence,
This is a very common issue. The first thing to realise is that your backup is probably still perfectly fine.
I'll start with a side-note. It appears you are doing "per mailbox" backups. Are you also backing up your Information Store? This will be what you will want in a disaster- not the mailboxes. Start by asking if this is really what you want. Usually it isn't, and by coming to that conclusion, you prevent yourself having to deal with this issue.
Mailbox backups unfortunately have this particular issue, due to their nature. Anything Outlook is going to have an issue reading, so too will BE.
Here are some simple steps
- Try uninstalling your virus scanner. If this product is blocking access to infected emails in an inbox, this will occur.
- Try to locate the defective email or calendar item and delete it. Unfortunately, your error is less descriptive than most, in terms of its ability to help you locate the email in question. Have a look through the Calendar of "Username" and see if you can see anything curious or out of place.
- Run an eseutil/isinteg combo to verify your Exchange database is good.
