## TL;DR
Open the dashboard filter settings and map the filter to a real field on every card it should control, because an unmapped filter either does nothing or, with a required default, filters on nothing and empties the card. Connect each card, set the field the filter drives, and test with two different filter values. A question that returns rows alone but empties on the dashboard is the clear signature.

```text
Metabase question returns empty dashboard: filter mapping failed error fix
```

## Use this when
- A card returns rows on its own page but is empty when viewed on the dashboard.
- A dashboard filter was added or a card was replaced and the card went empty afterwards.
- Changing the dashboard filter never changes the card, or empties it for every value.

## Not for this skill when
- The question itself is empty everywhere. Debug the question and the source data first.
- The card shows an error banner. That is a query failure, not a filter mapping gap.

## Steps
1. Open the saved question on its own and confirm it returns rows with no dashboard filter applied. Verify: the standalone question returns the expected row count
2. Edit the dashboard, open the filter settings, and check the card wiring panel for the failing card. Verify: the card either has no field mapped or maps to a field that no longer exists
3. Map the filter to the correct field on the card, choosing the field whose values match the filter type, such as a date field for a time filter. Verify: the wiring panel saves the mapping without a warning
4. For a native question card, confirm the query contains the variable the filter drives and that the variable type matches the filter. Verify: running the card with two filter values returns different, correct row sets
5. Save the dashboard, clear any required default that excludes all data, and reload as a viewer. Verify: the card shows data on load and responds to filter changes
6. Check the remaining cards on the dashboard for the same missing wiring so the filter behaves consistently. Verify: every card the filter claims to control changes when the filter changes

## Why it happens
Filter wiring is stored per dashboard and per card, so edits that replace a card, rebuild a question, or rename a field silently drop mappings that used to work. Because an unmapped filter often fails quietly, teams misread the empty card as a data outage. Testing the question standalone first separates the two causes in under a minute.

Metabase dashboard filters do not guess their targets. Each filter must be wired to a field on each card, and for native questions to a variable in the query. When the wiring is missing or points at a field removed in an edit, the card receives a filter it cannot apply. With certain filter types and defaults the result is an empty card with no error, which makes the problem look like missing data rather than missing mapping.

Field notes for Metabase specifically. The admin troubleshooting area, the task history, and the application database query tools give the evidence for most incidents, and the audit views on paid plans show who changed a question or a dashboard and when. Metabase behaviour differs meaningfully between the open source and paid builds, and between the application database choices underneath, so note the exact version when filing or searching for an issue. A question that works in the editor but fails on a dashboard is almost always a dashboard layer setting, which is why the two surfaces should always be tested separately.

For Metabase teams, models are the control point worth investing in. Questions built directly on raw tables inherit every schema change at full force, while models give the team one place to absorb a rename or a type change before it reaches fifty saved questions. Keeping production dashboards on models, and raw table questions in a clearly marked sandbox collection, measurably reduces breakage after warehouse changes. It also gives the schema sync somewhere forgiving to land, since the model owner sees the change before viewers do.
## Variants and edge cases
### Metabase dashboard filter not connected card empty
The wiring phrasing that names the missing connection.
### Metabase card empty on dashboard but works alone
The comparison phrasing users search when the standalone test passes.
### Metabase filter mapping removed after question edit
The edit-triggered variant where a rebuild dropped the mapping.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_HemdEh6SNdpBZvxz4rqcKQ