How do I clear the roster safely?

From the School Administrator manual, "Clearing the Roster (Danger Zone)".

Senior Admin only, and genuinely destructive — this cannot be undone. Found on School Settings (School Settings) (/school-settings), in a red-bordered Danger Zone section.

This permanently deletes every student in your school. Use it only for a genuine full reset (e.g. starting a new school year from scratch with a fresh import) — not for removing individual students, which you should archive or delete one at a time instead (see The Student Roster).

To confirm: type DELETE (exactly, in capitals) into the confirmation field, then click Clear roster.

Warning shown if you (or another admin) are also a parent here. If any Senior or Junior Admin at your school is also linked as a parent to a student, clearing the roster deletes that link, and re-importing the roster does not bring it back (the admin would have to be re-linked by hand). When this applies, the Danger Zone shows an amber warning listing exactly which admins (by email) would be affected, and the Clear roster button will not work until you also tick I understand the admin(s) listed above will lose their linked-student access and that re-importing will not restore it. If no admin is affected you see no warning and no extra checkbox. To refresh the roster for a new year without this risk, use the CSV re-import on the Import Students page instead of clearing first.

Clearing the roster removes every parent's linked students, so their accounts are automatically deactivated (they've nothing left to do at your school). When you re-import for the new year, any returning family reactivates automatically as soon as their student is linked again — you don't need to manually reactivate anyone (see Members — Parents, Password Resets, and Student Links).