The Error test is run in the Nero DiscSpeed – Advanced DAE Error Correction Test window.   
The results are displayed in the C2 errors and Compare errors graphs, as well as in the display areas underneath, while the test is still in progress. The top graph shows C2 errors found on the disc. The bottom graph compares the errors found when Nero DiscSpeed compares the data on the disc with the data from the image file.
The following fields are available in the areas below the graphs:
Position
Continuously indicates the current position of the read head on the disc over the course of the write process.
Elapsed
Specifies in minutes and seconds the time elapsed since the write process started.
C2 accuracy
The C2 accuracy of the optical drive is determined based on the results of the test.
Quality score
A percentage is calculated based on the results of the test. A quality index of 100% is perfect, i.e. there were no errors.
C2 errors
Shows the number of C2 errors found.
C2 missed
Shows the number of C2 errors missed.
Compare errors
Shows the number of compare errors found.
Compare errors occur when the audio data read out does not match the compare data from the image file.
Sync Errors
Shows the number of synchronization errors found.
Synchronization errors occur when data is correct but has been moved by one or more sectors.
C2 errors
A C2 error describes the error rate on the lower layers of a burned CD that are automatically corrected during reading. Every recordable disc features these errors; the fewer they are, the better the quality. High C2 error rates indicate burn problems or quality flaws.


Advanced DAE Error Correction Test Window