Even experienced users can make mistakes in QuickBooks that lead to inaccurate reports or compliance issues. Common errors include miscategorizing transactions, failing to reconcile bank accounts, skipping regular backups, ignoring undeposited funds, and not keeping chart of accounts clean. These mistakes can distort financial data and complicate tax filings. Avoid them by setting up clear accounting practices, using bank feeds correctly, reconciling monthly, and regularly reviewing reports. Using accountant review mode and scheduling periodic check-ins can help catch errors early. Understanding and preventing these mistakes ensures smoother operations and more accurate financial records for your business.