> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sampler.meiji.industries/llms.txt
> Use this file to discover all available pages before exploring further.

# MIDI And Sync Problems

> Troubleshoot MIDI mapping, monitor, transport, and controller connection issues.

# MIDI and sync problems

## A controller movement does nothing

Check in order:

1. Open Settings with `,`, then open the MIDI page.
2. The Monitor sub-view shows incoming events when you move the control. If not, the device is not connected or not sending on the expected channel.
3. A mapping exists for that control in the Mappings sub-view.
4. The mapping points to the correct action.
5. The current view allows MIDI pass-through (see below).

## MIDI mappings stop working in certain views

For direct app-action mappings, this is expected. Pad, loop, scene, transport, and mixer mappings only fire on the main sampler rows (Pads, Loops, Scenes), Channel Detail, Channel Chop, and the Help overlay. They are intentionally blocked in stateful modals and views such as Settings, Bounce, Trim, Search, MIDI Learn, and others to prevent mapped actions from silently dismissing those screens.

Keypress mappings are an exception. Once the MIDI control is resolved, the captured key goes through the normal keyboard handler, so it follows the active context. For example, a MIDI pad mapped to `1` can set or trigger marker `1` in the Trim/chop editor.

To restore direct-action MIDI response, close the modal or view and return to a main sampler row or channel overlay.

See [MIDI Implementation — Route allowlist](/reference/midi-implementation#route-allowlist) for the full list.

If the monitor shows events but the mapping does not fire, verify the mapping was saved — the status bar confirms each assignment.

## A mapping I just created is not listed

The Mappings sub-view shows a snapshot taken when you entered the tab. If you suspect a display issue, leave the MIDI page with `Esc`, then reopen Settings with `,` and return to MIDI to refresh the snapshot.

## A mapping disappeared after I assigned a new one

Mappings are one-to-one. One situation causes automatic removal:

* **Same control, new action**: Assigning a control to a different action replaces the old action for that control.

If a mapping vanished, that control was edited from the Listening list or reassigned in a separate step.

## I moved a mapped control and saw `already mapped`

This means the MIDI control you moved already has a mapping. MIDI Learn returns to the Listening list and selects that mapping row. Press `Enter` on the selected row to edit it, or move a different unmapped control to create a new mapping.

## I selected an action and saw `already mapped`

This means the action you selected is already mapped to a different MIDI control. MIDI Learn returns to the Listening list and selects the row for the existing mapping so you can inspect or edit it.

## I accidentally cleared all mappings

`Shift+Delete` in the Assigning phase clears every mapping. There is no undo for this operation. You will need to re-create your mappings.

## Transport messages show in the monitor but do not affect playback

The `transport_enabled` setting is off. Open Settings (`,`) and enable MIDI transport response.

## The monitor is unreadable or flooding

Clock and Active Sensing messages can generate very high volume. Press `f` in the Monitor sub-view to cycle through filters and suppress noise. Treat these message types as noise unless you are specifically diagnosing a sync problem.

## No MIDI devices appear

Meiji Sampler uses the system MIDI stack. Check:

* The controller is powered on and connected via USB or a MIDI interface.
* The device appears in your operating system's MIDI settings (macOS: Audio MIDI Setup).
* No other application has exclusive access to the device.

## Related pages

* [MIDI Implementation](/reference/midi-implementation) — control identification, mappable actions, and behavior details
* [MIDI and External Gear](/guides/midi-and-external-gear) — mapping workflow guide