Thank you for your reply. The only possible explanation on your list is that my data was damaged yesterday when I updated my software. 

Last week, all accounts were correctly reconciled. I opened QB yesterday, updated the software from the popup box, entered one month's data, went to reconcile those entries and found that the ending balance from the previous month's reconciliation was wrong. When I went to undo that last reconciliation, those numbers were wrong too. When I ran a discrepancy report, it showed 5 transactions listed as deleted. I did no such thing. Between last week's successful reconciliation and entering yesterday's transactions, the only variable is the software update. I rolled back to the previous backup and all that did was delete my work from yesterday; the prior month's ending balance was still wrong.  

How do I take the software back to before the update yesterday? This is very frustrating! I appreciate any help you can give me.