what is ultradma crc error count it is: the total quantity of crc errors during ultradma mode the raw value of this attribute indicates the number of errors found during data transfer in ultradma mode by icrc (interface crc) if the attribute gets higher with time or if you are starting to experience slow reads writes on your hdd then it is probably a fauly cable consider replacing the faulty cable if it stays at 2 then there is nothing to be worried about your pc is fine i attached a picture of a faulty hdd as you can see the ultradma crc error count is 16387