Printronix: GAP NOT DETECTED A “GAP NOT DETECTED” error means that the printer was not able to find the gap/mark between labels. There are a few potential causes for this error: The printer has not performed a media calibration on the labels Solution: Calibrate your printer. The labels are not feeding out of the printer correctly (most often because the labels were back-fed too far into the printer) Solution: Ensure that at least 1 label is sitting past the platen roller . The media sensor is in the wrong place (it should be underneath the labels, lined up with the gap) Solution: Ensure that the media sensor is sitting directly under the labels, so the gap between the labels will pass over the sensor when feeding/calibrating. After adjusting the sensor, please calibrate your printer again. The printer is set to the wrong media type (Gap vs. Mark) Solution: Ensure that the Sensors > Control > Gap/Mark Sensor is set to the value that matches your labels (e.g. Gap).