cashing a check for less then the amount owed

Cashing a check that does not have a restriction in the endorsement section (the reverse side of the check), a notation in the check memo or check stub such as "payment in full" or is accompanied by a letter saying the payment is provided in settlement of the dispute shouldn't result in your inability to request the balance of what is owed. But, if the buyer has provided anything in writing (including an e-mail) with the payment indicating there is a dispute and the check is an offer to settle, then your acceptance could prevent you from obtaining the balance you feel is owed. If you wish to be careful, do not accept the check, hold it, and inform the buyer that it will be returned when you receive the full payment. If you are comfortable with more risk, you could probably cash a check that is tendered without conditions.