Appraisals can be challenged when a transaction falls apart or a property value is questioned after the fact. If a client alleges your valuation was inaccurate or failed to consider key factors, professional liability insurance, also known as errors and omissions, can help. You appraise a commercial property for a refinance. Months later, the lender claims the valuation was overstated and contributed to financial loss. Professional liability insurance could help cover legal defence costs and potential damages.