Installing Windows Store apps to an SD card or another drive can be a breeze. Here are some tips to help you get started:

  1. Choose the right storage device. When you install an app to an SD card, make sure the storage device is compatible with the app. For example, if the app is a Windows Store app, make sure the storage device supports SD cards. If the storage device doesn’t support SD cards, you’ll need to find another way to install the app.
  2. Connect your phone and computer. Make sure your phone is connected to your computer by using a USB cable and your computer’s USB port. If you’re installing an app from scratch, connect your phone and computer together before starting installation.
  3. Choose a location for installation. When you’re installing an app from scratch, choose a location that’s easy for you to find (for example, on your desktop). You can also choose a location that’s easy for other people to find (for example, on a website).
  4. Follow installation instructions carefully. Follow installation instructions carefully so that you don’t lose any data or damage your computer during installation process.

Windows 8 installs applications to your C:\ drive by default, but you may want to change where Windows 8 stores these apps. For example, you could install them to an SD card or secondary hard drive.

This works on both Windows 8 and Windows RT. It’s useful whether you are using a Microsoft Surface, another Windows 8 tablet, or just a computer with a small SSD and a larger secondary drive.

Prepare the New Drive

Before we begin, we  must prepare the new install location. First, open a File Explorer window. Right-click the drive where you want to install Windows 8 apps – whether it’s an SD card, hard drive, or whatever else – and select Properties.

Ensure that the drive is formatted as NTFS.

If the drive isn’t formatted as NTFS, you will need to format the drive as NTFS to continue. (Many SD cards are formatted with the FAT file system instead.)

Back up any important data from the drive before continuing – formatting will delete all data on the drive. Right-click the drive and select Format.

Choose the NTFS file system and click Start.

You will want to create a folder for the apps on the drive. You can name it whatever you like, such as WindowsApps or Windows8Apps.

Change the Registry Setting

You will now need to open the registry editor. Press the Windows key, type regedit at the Start screen, and press Enter.

Navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Appx key.

Select the Appx key, click Edit, and click Permissions. (Ensure the Appx key is selected or you’ll modify permissions for another key instead!)

Click the Advanced button.

Click the Change link next to TrustedInstaller.

Type Administrators into the box, click Check Names, and click OK. This will give all administrators on the computer ownership of the registry key.

Enable the Replace owner on subcontainers and objects checkbox and click OK.

Select Administrators in the Permissions for AppX window and click the Allow option next to Full Control. Click OK and you will now be able to edit the appropriate registry setting.

Double-click the PackageRoot value in the right pane and enter the location of the folder you created earlier. That’s E:\Windows8Apps\ in the case of our example.

Reboot your computer. Your changes won’t take effect until you reboot.

Move Old Apps to the New Location [Optional]

This will only affect apps you install in the future. Previously installed apps will remain at the old location. To move these apps to the new location, you can uninstall them from your computer and then reinstall them from the Windows Store.

Thanks to tamarasu on the XDA Developers forum for first discovering this geeky trick!