Start by identifying what kind of error you’re dealing with. A miscategorized expense is a different problem than a bank reconciliation that won’t balance. The fix depends entirely on what went wrong.

Wrong categories are the easiest to correct. Open the transaction, change the category or account, and save. QuickBooks updates everywhere that transaction appears. If you’ve been miscategorizing the same type of expense repeatedly, use Find and Replace or edit transactions in bulk from the register view.

Duplicate transactions happen frequently when bank feeds and manual entries overlap. Delete the duplicate, but first make sure you’re removing the right one. If the duplicate was already reconciled, you’ll need to unreconcile it first or the deletion will throw off your bank balance.

Bank reconciliation errors are trickier. If you closed a reconciliation with a discrepancy, QuickBooks created an adjustment entry to force the balance. Find that adjustment in the reconciliation discrepancy account and investigate what caused it. Usually it’s a transaction that was edited after reconciliation, a deleted transaction, or something dated incorrectly. Fixing it means finding and correcting the underlying transaction, then possibly re-reconciling that period.

Opening balance issues cause problems that ripple through your entire file. If your beginning balances are wrong, every report that relies on them will be wrong too. This usually requires journal entries to correct and sometimes means working backward through historical periods to find where things went off track.

Before making any corrections, create a backup of your file. QuickBooks maintains an audit trail of changes, but having a backup lets you restore if a fix makes things worse. Go to File, then Back Up Company, and save it somewhere you can find it.

Some errors are straightforward enough that you can handle them yourself. Others are symptoms of deeper problems with how the file was set up or maintained. If you’re spending hours trying to get reports to match or your accountant keeps finding issues during small business tax preparation, the file might need more than spot corrections.

QuickBooks setup and training often includes cleaning up existing files. Sometimes a few hours of professional work can straighten out problems that would take you days to untangle. If you’re not confident about what you’re fixing or why, that’s usually a sign to get help before making changes that create new problems.