---
title: File check
description: File check in Zero Trust.
image: https://developers.cloudflare.com/zt-preview.png
---

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# File check

The File Check device posture attribute checks for the presence of a file on a device. You can create multiple file checks for each operating system you need to run it on, or if you need to check for multiple files.

## Prerequisites

* Cloudflare One Client is [deployed](https://developers.cloudflare.com/cloudflare-one/team-and-resources/devices/cloudflare-one-client/deployment/) on the device. For a list of supported modes and operating systems, refer to [Cloudflare One Client Checks](https://developers.cloudflare.com/cloudflare-one/reusable-components/posture-checks/client-checks/).

## Configure a file check

1. In the [Cloudflare dashboard ↗](https://dash.cloudflare.com/), go to **Zero Trust** \> **Reusable components** \> **Posture checks**.
2. Go to **Cloudflare One Client checks** and select **Add a check**.
3. Select **File Check**.
4. You will be prompted for the following information:

  1. **Name**: Enter a unique name for this device posture check.
  2. **Operating system**: Select your operating system.
  3. **File Path**: Enter a file path (for example, `c:\my folder\myfile.exe`).  
  Environment variables  
  File paths can include environment variables to account for differences across devices. Environment variables are resolved in the context of the Cloudflare One Client daemon, not the logged-in user. Only variables available to the daemon process at runtime will work.

    * **Windows**: Use `%VAR%` syntax. For example, `%PROGRAMFILES%\myfolder\myfile.exe`.
    * **macOS/Linux**: Use `${VAR}` syntax. For example, `${RUNTIME_DIRECTORY}/myfolder/myfile`.
  4. **Signing certificate thumbprint (recommended)**: Enter the [thumbprint](https://developers.cloudflare.com/cloudflare-one/reusable-components/posture-checks/client-checks/application-check/#determine-the-signing-thumbprint) of the publishing certificate used to sign the file. Adding this information will enable the check to ensure that the file was signed by the expected software developer.
  5. **SHA-256 (optional)**: Enter the [SHA-256 value](https://developers.cloudflare.com/cloudflare-one/reusable-components/posture-checks/client-checks/application-check/#determine-the-sha-256-value) of the file. This is used to ensure the integrity of the file on the device.
5. Select **Save**.

Next, go to **Insights** \> **Logs** \> **Posture logs** and verify that the file check is returning the expected results.

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```