This error arises when the school has not entered Class Information on the front page of the Census. Click on 'Return to Census Page' at the top right of the screen (or go to Admin > Census > Spring Census)
Under 'Spring Census Specific Data' you will find the area where Class Information needs to be manually entered for the Spring Census.
Click on 'Class Details' to enter figures in the top section and click Save at the bottom of the tables.
Then click on Add New to the right of the screen, to add information for class activity. The figures entered here will fill the middle and lower boxes above. Total numbers of students will need to agree with your number of pupils on roll on Census Day (check Reporting > Reports > Students tab > On Roll by Date report for the Census date).
For full information on the Census Specific Data that needs to be manually input for Spring Census, including the time of day to record each lesson activity, click here.