My Bank reconciliation is a mess. Starting balance from last month is off. Items reconciled last mo

Starting Balance in a reconciliation is the sum of ALL (past or future) transactions in the account that are marked with an "R" in the CLR column.

SO, did you manually change any CLR value in the account for any transaction? OR, if a transaction was a transfer to another account in Q, did you change the CLR value of the other side of the transfer … which inappropriately changes the CLR value in both sides. OR did you delete, or manually add, an "R" transaction?

OR, did you change the download method into the account? Say, from Direct Connect to Express Web Connect(+)? There's a long-standing bug in Q that can cause such actions to change the Opening Balance in the account … which is why it's suggested to record the correct Opening Balance in the Memo field of the OB transaction so if/when it happens it's easier to spot and to know what the correct amount should be.

IF an OB amount change is the cause you can look back to prior months and see if the balance on the prior statement date matches between Q and your bank statements. If you go back several time periods (say 3 month jumps at a time) and many of them are off, suspect an OB change.

What you can do to be certain is to restore from a backup created before the download change and see what the OB was at that time. It's possible that you'll have to open several backups before you find one with the correct amount (assuming, of course, that you don't simply have paper statements that go back far enough).

IMPORTANT, when you restore such backups, don't "overwrite" your current production file. Use a name for the restored file that's somehow different from production.