If when looking in Register > Manage Register, there is a student greyed out for some days or maybe the whole week, this is caused by there being a leaving date in the student profile.
Teachers can still add attendance codes for the student via their register, but the codes will be hidden in Manage Register.
To correct this, click on the students name to open their profile or search for them using the search box in the top right of ScholarPack.
Click on the Extended tab and scroll down to the School Information section.
Remove the leaving date and then save the record.
Any codes already added by teachers in their register will then be revealed when viewed in Manage Register and gaps will also be visible -