More important than the date the check was written is the date the check cleared. The state UCC provides for one year from the date of the statement in which the item posted for a customer to bring a claim of forged drawer's signature to you. The UCC also gives you the ability to shorten this timeframe by agreement. If you are using standard boilerplate language for your deposit account agreement, your customer probably has a thirty or sixty day window to report the forgery. Either way, if that check cleared shortly after it was written, your customer will need to take his claim directly to the offending party (the forger) and/or law enforcement. It is not the bank's cross to bear this long after the fact.