# Create a Large File for Testing

> How to generate a dummy file for testing upload and download speeds.

:::warning
**This article provides instructions for utilising command line tools**. While we strive to offer accurate and clear guidance, it is essential to exercise caution and comprehension when working with command line interfaces (CLI). Command line operations can impact your system, files, and data, and incorrect usage may lead to unintended consequences, including data loss or system instability.
:::

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The DekkoSecure application does not have file size limits. If you are participating in a DekkoSecure trial using dummy data and/or need to test the performance of the application without uploading sensitive material, you can easily create an test file of any size. The files created by following this guide are simply blocks of “empty” data, so they cannot be read - but they will report having a size that you specify. Uploading, downloading and sharing these files in the DekkoSecure application will reflect the same experience as interactions using your real files.

:::tip
**Note:** make sure you have enough disk space on your computer before creating large files!
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## Create a large file on Windows

A file of any size can be created using the **fsutil** command ([learn more](https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/fsutil-file)).

**Steps for creating a large file:**

1. Open **Command Prompt** ([see how](https://en.wikiversity.org/wiki/Command_Prompt/Open#:~:text=Open%20the%20Start%20menu%20or,Press%20Enter.)).
2. Navigate to a directory where the new large file will be stored using the **cd** command. For example, **cd %YOUR_USERNAME%\Desktop** to navigate to your desktop folder. ([learn more about file system navigation in Command Prompt](https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/cd)).
3. Enter your **fsutil** command, for example, **fsutil file createnew test_file 5000000000**.

You can use [this tool](https://www.gbmb.org/gigabytes) to convert a desired file size to bytes.

This will create a 5GB file called *test_file* in your desktop folder.

:::success
That's it! You are ready to upload and share your large file.
:::

## Create a large file on a Mac

A file of any size can be created using the **mkfile** command ([learn more](https://ss64.com/mac/mkfile.html)).

**Steps for creating a large file:**

1. Open **Terminal** ([see how](https://support.apple.com/en-au/guide/terminal/apd5265185d-f365-44cb-8b09-71a064a42125/mac)).
2. Navigate to a directory where the new large file will be stored using the **cd** command. For example, **cd desktop** to navigate to your desktop folder. ([learn more about file system navigation in Terminal](https://ss64.com/mac/cd.html)).
3. Enter your **mkfile** command, for example, **mkfile -n 5g test_file**.

This will create a 5GB file called *test_file* in your desktop folder.

:::success
That's it! You are ready to upload and share your large file.
:::