**Source URL:** https://limited.veevavault.dev/medical/library/guides/creating-custom-packages.md

# Creating Custom Configuration Migration Packages

This guide provides instructions on how to manually edit existing configuration migration packages (VPKs) to create [custom VPKs](/library/references/about-configuration-migration-packages#Custom_VPKs). You can find instructions for [creating and deploying Vault-generated VPKs in Vault Help](https://platform.veevavault.help/en/lr/36919).

## Prerequisites {#prerequisites}

Before you begin, ensure that you are able to change file extensions and zip and unzip files.

## Changing the File Extension {#Change_Extension}

As a prerequisite to creating custom VPKs, you must be able to change the extension of files.

<Steps>
1. Enable file name extensions as follows:

<Tabs><TabItem label="Windows">Enable file name extensions by opening File Explorer and selecting **View > Show > File name extensions**.

</TabItem><TabItem label="Mac">Enable showing all filename extensions by opening Finder and selecting **Finder > Settings > Advanced > Show all filename extensions**.

</TabItem></Tabs>

2. Once it is visible, you can use **Rename** to change the file extension to `.vpk` for the package. Or, you can also use the terminal with the following command:

<Tabs><TabItem label="Windows">
```
ren my_vpk_package.zip my_vpk_package.vpk

```
</TabItem><TabItem label="Mac">
```
mv my_vpk_package.zip my_vpk_package.vpk

```
</TabItem></Tabs>

</Steps>

## Extracting and Packaging VPK Content {#extracting-and-packaging-vpk-content}

Configuration migration packages (VPKs) are structured as ZIP archives, and their content can be extracted (unzipped) and packaged (zipped) with any conventional tool that handles `.zip` files. These steps are not required when working with Vault-generated VPKs that you do not wish to modify.

### Extracting VPK Content {#extracting-vpk-content}

You can extract VPK content by renaming the file from `pkg_name.vpk` to `pkg_name.zip` on your computer, and then unzipping the archive.

### Packaging VPK Content {#packaging-vpk-content}

You can package VPKs by creating a ZIP archive. VPKs must have at least one `components` folder or one `javasdk` folder (or both) to be a valid package. When all steps are ready to package, select the `components` folder, `javasdk` folder, and the `vaultpackage.xml` file and compress them into a `.zip` file. Then change the file extension from `.zip` to `.vpk`. Learn more about [VPK contents](/library/references/about-configuration-migration-packages#VPK_Contents).

## Creating Your First Custom VPK {#creating-your-first-custom-vpk}

Perform the following steps to create a new *Picklist* component and deploy it with a VPK that you can import to any Vault:

<Steps>
1. Create a folder where you will build the VPK, for example, `my-first-vpk`.

2. In the `my-first-vpk` folder, create a folder called `components`.

3. In the `my-first-vpk` > `components` folder, create a folder called `00010`. This folder represents the first deployment step.

4. Open a new file in a text editor and paste the following [MDL](/mdl/documentation/mdl-commands/recreate) to create a [Picklist](/mdl/component-reference/component-types/picklist) component:

```
RECREATE Picklist my_first_picklist__c (
   label('My First Picklist'),
   active(true),
   can_add_values(true),
   can_reorder_values(true),
   Picklistentry my_first_picklistentry__c(
      value('My First Picklistentry'),
      order(1),
      active(true)
   )
);

```

5. Save the file in the `my-first-vpk` > `components` > `00010` folder as `Picklist.my_first_picklist__c.mdl`

6. Open a new file in a text editor where we’ll create the MD5 Checksum file.

7. [Generate the MD5 checksum](/library/references/about-configuration-migration-packages#Generate_MD5) for the `Picklist.my_first_picklist__c.mdl` file.

8. Paste the MD5 checksum to the text editor, followed by a space and `Picklist.my_first_picklist__c`, as shown below:

```
<md5_checksum_value> Picklist.my_first_picklist__c

```

9. Save the file as `Picklist.my_first_picklist__c.md5` in the `my-first-vpk` > `components` > `00010` folder.

10. Open a new file in the text editor and paste the following XML:

```
<vaultpackage xmlns="https://veevavault.com/">
<name>my-first-vpk-package</name>
<source>
    <vault>999999</vault>
    <author>your.email@yourcompany.com</author>
</source>
<packagetype>migration__v</packagetype>
<summary>My First VPK Package</summary>
<description></description>
</vaultpackage>

```

11. Save the file as `vaultpackage.xml` in the `my-first-vpk` folder.

12. Select the `vaultpackage.xml` file and the `components` folder and create a ZIP archive from them with your preferred method.

13. [Change the extension](#Change_Extension) of the file from `.zip` to `.vpk`.

14. Within Vault, [import the VPK package](https://platform.veevavault.help/en/lr/36919#import) by navigating to **Admin > Deployment > Inbound Packages** and clicking **Import**.

15. [Deploy the VPK package](https://platform.veevavault.help/en/lr/36919#deploy) by clicking the imported package, clicking **Review & Deploy**, and following the on-screen instructions.

16. Once the deployment is complete, verify the existence of the new picklist in **Business Admin**.

</Steps>

## Troubleshooting Deployments {#troubleshooting-deployments}

When deploying VPKs, you may encounter errors and warning messages. The most common ones are documented in [Configuration Migration Errors & Warnings](https://platform.veevavault.help/en/lr/39591). If you have trouble understanding an error message, you can reach out to the [Vault Developer Support Community on Veeva Connect](https://veevaconnect.com/communities/ATeJ3k8lgAA/about).