At a glance

A manually placed lesson has the pin flag set but no actual time slot or week is stored.

What causes this error

A lesson has the "pinned" flag set (locked in place in the timetable), but no time slot or week is actually stored alongside it. The lesson is marked as pinned but there is nothing to pin it to.

The most common scenario is regenerating/evaluating a timetable after the school periods were changed. If you modified (added, removed, or reordered) periods after the previous generation, some pinned lessons may have lost their time reference when the timetable was reset.

How to fix it

There are two directions you can take:

Adapt the timetable to match the current school configuration:

• Open the timetable editor, locate the lesson, and unpin it so the scheduler can place it automatically using the current periods.

Adapt the school configuration to match the timetable:

• Go to School Config → Periods and restore the period configuration that was in place when the timetable was generated, so the pinned lessons have valid slots to reference again.

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