Missing tasks
A task you expected is not in your filter, Calendar, or Kanban. The good news is that your task is almost certainly safe: tasks live in your Markdown, and the views are built from an index of them. "Missing" usually means the index or the view, not the task. Work through these in order.
Is it indexed?
Operon shows tasks from an index built from your notes. If the index is out of date, a real task can be absent from views. Run Show index stats to see the totals Operon currently knows about, and if they look wrong, run Rebuild full index to re-scan the vault. This is the first thing to try, and it fixes most cases, especially after editing files outside Obsidian. See Markdown task storage.
Is the note in an excluded folder?
Operon can be told to ignore folders. Tasks in an excluded folder stay outside the index and every view on purpose, so a task there will not appear. If a task is missing, check whether its note sits in an excluded folder, and remove that folder from the exclusions if it should be indexed.
Is it actually a task?
Operon only shows lines it recognizes as tasks. A line that lost its operonId, or a checkbox that was never converted, is not an Operon task and will not appear. Open the line and convert or recreate it as a proper task. See Inline tasks.
Is it just filtered out?
A task can be indexed and present but hidden by the view you are looking at. A filter that excludes its status or date, or a Kanban board on a different pipeline, will not show it. This is not a missing task; it is a view choice. Widen the filter or check a different view. See Filter View.
Could it be a duplicate conflict?
If a task shares its operonId with another, Operon may block or confuse it until the conflict is resolved. Check for a duplicate alert and open the conflict manager. See Duplicate IDs.
FAQ
Did I lose the task? Almost never. Tasks are in your notes. Check the note directly; if the text is there, the fix is reindexing or a view change.
Rebuild did not bring it back. Now what? Confirm the note is not in an excluded folder, and that the line is a real Operon task with an operonId.
Why would a whole folder of tasks be missing? That folder is probably excluded from the index.
Settings
Excluded folders are set in Settings → Operon → Tasks → File Tasks. Tasks in those folders are intentionally kept out of Operon's index and views.