A system and method identifies and masks physical sectors where the errors encountered during the defect scan exceed a predetermined level. This avoids the need to read and process all the data written to an individual sector during the initial defect scan. This method first writes a predetermined pattern such as a 2-T pattern to the magnetic media available for user data. This written pattern is then read. As the pattern is read, an error result increments or decrements a counter based on the error. The counter reaching a predetermined level signifies that there are too many errors in this physical sector. This sector may then be added to the primary defect list and masked out without reading the remaining written pattern within the sector. This will result significant time savings as physical sectors containing multiple errors are identified without process all the information written to the physical sector. The primary defect list is used during the low-level format to map logical locations to physical locations.