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# Let viewers refresh a collection's data by upload

> Turn on Data refresh for a Mammoth collection so the people it's shared with can upload CSV or XLSX files that update its dashboards through an automation.
>
> Applies to: Roles: Project Admins and Project Editors of the collection's project turn it on; viewers upload. Where: Dashboards › a collection › ⋯ › Data refresh…

Data refresh lets the people a [collection](https://mammoth.io/docs/learn/share-and-export/collections/) is shared with update its dashboards by uploading a file. It runs through an automation in the collection's project that has a source folder and destination datasets, such as a [Combine incoming data](https://mammoth.io/docs/learn/automate/consolidate/) automation. Turn it on from the collection header's **⋯** → **Data refresh…**.

## Turn on Data refresh

1. In the collection header, open **⋯** → **Data refresh…**.
2. Pick the **Automation**. Only automations in the collection's own project are listed. With none, the dialog says "No automations in this project yet."
3. Click **Save**. You see "Data refresh updated".

The header then shows **Data refresh**. To stop it, open the same dialog and click **Turn off data refresh**.

| Message | Why |
| --- | --- |
| "The selected automation has no source folder" | The automation has nowhere to receive files |
| "The selected automation has no destination datasets" | The automation doesn't write to a dataset |
| "A collection can only refresh from an automation in its own project." | The automation is in another project |

## How viewers refresh the data

Viewers see **Refresh data** above the dashboards. It opens "Refresh data: Upload new files · Mammoth validates and appends automatically".

1. Drop CSV or XLSX files, or browse for them. Several can go at once.
2. **Format validation** checks each file against the automation's datasets.
3. Matching files are appended. When the run finishes, viewers see "Dashboards updated: Your dashboards now reflect the latest data".

To start from the right headers, open **Column templates** and click **Download** for a CSV with only the required headers. A file Mammoth can't read shows "Unsupported format", with **Delete file**.

## Related

- [Collections](https://mammoth.io/docs/learn/share-and-export/collections/): create and share the collection.
- [Combine incoming data](https://mammoth.io/docs/learn/automate/consolidate/): the automation behind Data refresh.
- [What viewers see](https://mammoth.io/docs/learn/share-and-export/what-viewers-see/): the collection from the viewer's side.

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Source: https://mammoth.io/docs/learn/share-and-export/collection-data-refresh.md · Updated: 2026-11-08