> For the complete documentation index, see [llms.txt](https://excelhelp.windhamlabs.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://excelhelp.windhamlabs.com/functions/general/xlablicense.md).

# XLABLICENSE

## Description

Excel Lab authenticates with Windham's licensing server for convenience and security. If you encounter issues with re-authentication, you will be able to manually invoke authentication my following the syntax as documented below in Excel's formula bar.

![A workbook using Excel Lab requiring re-authentication](/files/-MPeBxSIobRpVYOGf9W5)

{% hint style="info" %}
You can invoke Excel Lab's license authentication process anywhere in a workbook. You can even do this in a new blank workbook. 

You do not need to save the workbook once authentication is successful.
{% endhint %}

## Syntax

The following describes the function signature for use in Microsoft Excel's formula bar.

```excel-formula
=XLABLICENSE()
```

### Input(s)

Follow the on-screen dialog prompt to enter your username and password.

| Argument     | Description                                                                                                                           |
| ------------ | ------------------------------------------------------------------------------------------------------------------------------------- |
| **Username** | Your e-mail address registered with Windham Labs.                                                                                     |
| **Password** | <p>Your password, or unlock key code for offline use. <br>The offline unlock key code is only available for yearly billing plans.</p> |

### Output(s)

| Message                 | Description                                                                               |
| ----------------------- | ----------------------------------------------------------------------------------------- |
| **Valid**               | Credentials (username / password) and account successfully authenticated. Enjoy ExcelLab! |
| **Invalid Credentials** | Invalid username and/or password. Check for typos, try again.                             |
| **Inactive**            | Your account is no longer active.                                                         |
| **Invalid Permissions** | Your account is not permissioned for the product / feature.                               |
| **Expired**             | Your account has expired.                                                                 |
| **Invalid Host**        | Unauthorized device. Each Excel Lab license is locked to a device.                        |
| **Missing Credentials** | No input for either username or password. Please try again.                               |

## Example

![Invoke licensing via the Formula Bar](/files/-MPeGnpShvNvmbGtRFuG)

To manually authenticated

1. Open any workbook, or create a new (temporary) workbook.
2. In any cell, type `=XLABLICENSE()` in the formula bar.
3. Follow the instructions as described in the Syntax section above.

{% hint style="info" %}
When successful, Excel Lab will store your license information within user-specific system files. You do not need to save the temporary workbook.
{% endhint %}