A circuit and method uses CRC to check errors detected and corrected by an ECC unit (120) when reading data from a disk (116) in a disk drive (110). A CRC unit (118) monitors both the sector bytes read from the disk platter (114) and the error corrections made by the ECC unit (120) to the data and CRC bytes. The CRC unit (118) uses this information to determine whether the ECC-corrected data bytes stored in a buffer unit (122) were properly corrected. The CRC unit (118) reads data bytes and CRC bytes from the disk (116) simultaneously with the ECC unit (120). The CRC unit (118) begins generating a residue to detect errors in the data at approximately the same time the ECC unit (120) begins generating a residue to detect errors in the sector. The CRC unit (118) does not wait for the ECC unit (120) to finish and transfer the ECC error corrections into a buffer. The CRC error check is completed before any data is transferred to the host computer (112). In particular, the CRC unit (118) approves the data before the disk drive controller (126) sends the data to the host (112).