Trying to register windows app installer.

Question

I have Windows 10 IoT LTS. I got this message when entering this command

Add-AppxPackage -RegisterByFamilyName -MainPackage Microsoft.DesktopAppInstaller_8wekyb3

in Admin: Windows Powershell.

Add-AppxPackage : Deployment failed with HRESULT: 0x80073CF9, Install failed. Please contact your software vendor.

(Exception from HRESULT: 0x80073CF9)

Deployment operation failed.

NOTE: For additional information, look for [ActivityId] b025d7df-b698-0000-8feb-2bb098b6dc01 in the Event Log or use

the command line Get-AppPackageLog -ActivityID b025d7df-b698-0000-8feb-2bb098b6dc01

At line:1 char:1

• Add-AppxPackage -RegisterByFamilyName -MainPackage Microsoft.DesktopA ...

• 
      + CategoryInfo          : WriteError: (Microsoft.DesktopAppInstaller_8wekyb3:String) [Add-AppxPackage], IOExceptio
  
     n
  
      + FullyQualifiedErrorId : DeploymentError,Microsoft.Windows.Appx.PackageManager.Commands.AddAppxPackageCommand
  

Answer 1

Error 0x80073CF9 corresponds to ERROR_INSTALL_FAILED, which indicates that the package install failed and the detailed cause is only available in the deployment logs.

To proceed on Windows 10 IoT Enterprise LTSC:

1. Run the suggested logging command in the same elevated PowerShell session:

      Get-AppPackageLog -ActivityID b025d7df-b698-0000-8feb-2bb098b6dc01
   

   This will show the specific reason for the failure (for example, dependency, disk, policy, or signature issues).
2. Also check the AppXDeployment-Server event log, which is explicitly referenced for this error code:
   • Open Event Viewer.
   • Navigate to Applications and Services Logs → Microsoft → Windows → AppXDeployment-Server → Microsoft-Windows-AppXDeploymentServer/Operational.
   • Filter or search for the same ActivityId b025d7df-b698-0000-8feb-2bb098b6dc01.
   • Review the detailed error text and any inner error codes.
3. Based on the details found there, take the corresponding action. For example, for common causes listed in the documentation:
   • If the log shows ERROR_INSTALL_RESOLVE_DEPENDENCY_FAILED (0x80073CF3), install any missing dependency packages or correct architecture mismatches.
   • If it shows ERROR_INSTALL_OUT_OF_DISK_SPACE (0x80073CF4), free disk space and retry.
   • If it shows ERROR_INSTALL_POLICY_FAILURE (0x80073CFF), ensure the device is configured for sideloading or has the required developer/enterprise policy.
   • If it shows ERROR_PACKAGE_ALREADY_EXISTS (0x80073CFB), either increment the package version and reinstall, or remove the existing package for all users before re-adding it.

Without the additional detail from Get-AppPackageLog or the AppXDeployment-Server log, 0x80073CF9 only indicates a generic install failure, so the next step is to use those logs to identify the specific underlying error and then apply the matching resolution.

---

References:

• Troubleshooting packaging, deployment, and query of Windows apps

Answer 2

Hello Matthew Deng,

The error you’re seeing (HRESULT: 0x80073CF9) is a Windows AppX deployment failure. It’s not related to Windows for Business or Windows 365 Enterprise, but specifically to how Windows 10 IoT LTSC handles modern apps. Unlike standard Windows 10/11 editions, IoT LTSC has limited support for UWP apps, and certain packages like Microsoft.DesktopAppInstaller (App Installer) are not fully supported or may fail to deploy if the system is missing dependencies.

The command you used, Add-AppxPackage -RegisterByFamilyName, is not valid for this scenario. That parameter is intended for re‑registering packages already present in the system. On LTSC, the App Installer package is not included by default, and attempting to register it without the full package payload results in the deployment error you saw.

To troubleshoot properly, check the detailed log with:

Get-AppPackageLog -ActivityID b025d7df-b698-0000-8feb-2bb098b6dc01

This will show which dependency or capability is missing. In most cases on LTSC, the failure is because the Microsoft.VCLibs runtime or the DesktopAppInstaller dependency chain is not present. Without those, the package cannot be staged.

The supported way to install App Installer on LTSC is through the MSIX bundle provided by Microsoft, not by re‑registering. You need to download the official App Installer package from Microsoft Store for Business or from the Windows ADK/MSIX tooling. Once you have the .appxbundle or .msixbundle, install it with:

Add-AppxPackage -Path "C:\Path\To\Microsoft.DesktopAppInstaller.msixbundle"

If your environment blocks Store apps, you may not be able to use App Installer at all on LTSC. In that case, the recommended approach is to use winget or MSIX packaging tools only on supported editions, and rely on MSI/EXE deployment for LTSC.

I hope you've found something useful here. If it helps you get more insight into the issue, it's appreciated to accept the answer. Should you have more questions, feel free to leave a message. Have a nice day!

Domic Vo.