# Install the ENA driver on EC2 Windows instances
If your instance isn't based on one of the latest Windows Amazon Machine Images (AMIs) that Amazon provides, use the following procedure to install the current ENA driver on your instance. You should perform this update at a time when it’s convenient to reboot your instance. If the install script doesn’t automatically reboot your instance, we recommend that you reboot the instance as the final step.
If you use an instance store volume to store data while the instance is running, that data is erased when you stop the instance. Before you stop your instance, verify that you've copied any data that you need from your instance store volumes to persistent storage, such as Amazon EBS or Amazon S3.
## Prerequisites
To install or upgrade the ENA driver, your Windows instance must meet the following prerequisites:
+ PowerShell version 3.0 or later is installed.
+ The commands shown in this section must run in the 64-bit version of PowerShell. Do not use the `x86` version of PowerShell. That is the 32-bit version of the shell, and is not supported for these commands.
## Step 1: Back up your data
We recommend that you create a backup AMI, in case you're not able to roll back your changes through the **Device Manager**. To create a backup AMI with the Amazon Web Services Management Console, follow these steps:
1. Open the Amazon EC2 console at [https://console.amazonaws.cn/ec2/](https://console.amazonaws.cn/ec2/).
1. In the navigation pane, choose **Instances**.
1. Select the instance that requires the driver upgrade, and choose **Stop instance** from the **Instance state** menu.
1. After the instance is stopped, select the instance again. To create your backup, choose **Image and templates** from the **Actions** menu, then choose **Create image**.
1. To restart your instance, choose **Start instance** from the **Instance state** menu.
## Step 2: Install or upgrade your ENA driver
You can install or upgrade your ENA driver with Amazon Systems Manager Distributor, or with PowerShell cmdlets. For further instructions, select the tab that matches the method that you want to use.
------
#### [ Systems Manager Distributor ]
You can use the Systems Manager Distributor feature to deploy packages to your Systems Manager managed nodes. With Systems Manager Distributor, you can install the ENA driver package once, or with scheduled updates. For more information about how to install the ENA driver package (`AwsEnaNetworkDriver`) with Systems Manager Distributor, see [Install or update packages](https://docs.amazonaws.cn/systems-manager/latest/userguide/distributor-working-with-packages-deploy.html) in the *Amazon Systems Manager User Guide*.
------
#### [ PowerShell ]
This section covers how to download and install ENA driver packages on your instance with PowerShell cmdlets.
**Option 1: Download and extract the latest version**
1. Connect to your instance and log in as the local administrator.
1. Use the **invoke-webrequest** cmdlet to download the latest driver package:
```
PS C:\> invoke-webrequest https://ec2-windows-drivers-downloads.s3.amazonaws.com/ENA/Latest/AwsEnaNetworkDriver.zip -outfile $env:USERPROFILE\AwsEnaNetworkDriver.zip
```
**Note**
If you receive an error when downloading the file, and you are using Windows Server 2016 or earlier, TLS 1.2 might need to be enabled for your PowerShell terminal. You can enable TLS 1.2 for the current PowerShell session with the following command and then try again:
```
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
```
Alternatively, you can download the latest driver package from a browser window on your instance.
1. Use the **expand-archive** cmdlet to extract the zip archive that you downloaded to your instance:
```
PS C:\> expand-archive $env:userprofile\AwsEnaNetworkDriver.zip -DestinationPath $env:userprofile\AwsEnaNetworkDriver
```
**Option 2: Download and extract a specific version**
1. Connect to your instance and log in as the local administrator.
1. Download the ENA driver package for the specific version you want from the version link in the [ENA Windows driver version history](ena-driver-releases-windows.md#ena-win-driver-release-history) table.
1. Extract the zip archive to your instance.
**Install the ENA driver with PowerShell**
The install steps are the same whether you've downloaded the latest driver or a specific version. To install the ENA driver, follow these steps.
1. To install the driver, run the `install.ps1` PowerShell script from the `AwsEnaNetworkDriver` directory on your instance. If you get an error, make sure that you’re using PowerShell 3.0 or later.
1. If the installer doesn’t automatically reboot your instance, run the **Restart-Computer** PowerShell cmdlet.
```
PS C:\> Restart-Computer
```
------
## Step 3 (optional): Verify the ENA driver version after installation
To ensure that the ENA driver package was successfully installed on your instance, you can verify the new version as follows:
1. Connect to your instance and log in as the local administrator.
1. To open the Windows Device Manager, enter `devmgmt.msc` in the **Run** box.
1. Choose **OK**. This opens the Device Manager window.
1. Select the arrow to the left of **Network adapters** to expand the list.
1. Choose the name, or open the context menu for the **Amazon Elastic Network Adapter**, and then choose **Properties**. This opens the **Amazon Elastic Network Adapter Properties** dialog.
**Note**
ENA adapters all use the same driver. If you have multiple ENA adapters, you can select any one of them to update the driver for all of the ENA adapters.
1. To verify the current version that's installed, open the **Driver** tab and check the **Driver Version**. If the current version doesn't match your target version, see [Troubleshoot the Elastic Network Adapter Windows driver](troubleshoot-ena-driver.md).
## Roll back an ENA driver installation
If anything goes wrong with the installation, you might need to roll back the driver. Follow these steps to roll back to the previous version of the ENA driver that was installed on your instance.
1. Connect to your instance and log in as the local administrator.
1. To open the Windows Device Manager, enter `devmgmt.msc` in the **Run** box.
1. Choose **OK**. This opens the Device Manager window.
1. Select the arrow to the left of **Network adapters** to expand the list.
1. Choose the name, or open the context menu for the **Amazon Elastic Network Adapter**, and then choose **Properties**. This opens the **Amazon Elastic Network Adapter Properties** dialog.
**Note**
ENA adapters all use the same driver. If you have multiple ENA adapters, you can select any one of them to update the driver for all of the ENA adapters.
1. To roll back the driver, open the **Driver** tab and choose **Roll Back Driver**. This opens the **Driver Package rollback** window.
**Note**
If the **Driver** tab doesn't show the **Roll Back Driver** action, or if the action is unavailable, it means that the [Driver Store](https://learn.microsoft.com/en-us/windows-hardware/drivers/install/driver-store) on your instance doesn't contain the previously installed driver package. To troubleshoot this issue, see [Troubleshooting scenarios](troubleshoot-ena-driver.md#ts-ena-drv-scenarios), and expand the **Unexpected ENA driver version installed** section. For more information about the device driver package selection process, see [How Windows selects a driver package for a device](https://learn.microsoft.com/en-us/windows-hardware/drivers/install/how-windows-selects-a-driver-for-a-device) on the *Microsoft documentation website*.