[GNC] Non-zero starting balance?

[Bo Laurent]

I am a new gnucash user; I am preparing my records to share with my
accountant for the first time (previously using Quicken for Mac).

My checking account was balancing, for every statement from January 2018 to
Nov ember 2018, and I looked over a transaction report and changed quite a
few items.

Now my checking account has a strange starting balance (tens of thousands
of dollars, when it should never exceed 10,000). I decided to start from
zero by re-balancing November 1, 2017 (there are no transactions earlier
than Dec 21 2017). But strangely, the starting balance shows $48K. How can
a gnucash show a non-zero starting balance for an account when the
reconciliation date is earlier than the earliest entry?