Resolving 3CX Windows Softphone Issues

Introduction

As different Microsoft Windows PCs can have different exact Windows versions or upgrade histories, in some rare cases you might need to take steps to restore functionality of the 3CX Softphone.

This document covers some of the more common of these issues, and how to resolve them.

Windows Issues

Softphone starts but stays in the background

If your 3CX Softphone starts successfully, but does not automatically appear on the Desktop, follow this steps:

  • As a first step navigate to:

%localappdata%\Packages\3CXDMCC.3CX_97f1hnz6y6tba\LocalCache\Local\3CXSoftphone

OR

%localappdata%\Packages\3CXDMCC.3CX_bhm4yemhnd70e\LocalCache\Local\3CXSoftphone

OR  

%localappdata%\Packages\3CXDMCC.3CXBeta_bhm4yemhnd70e\LocalCache\Local\3CXSoftphone

  • and open the .log file.
  • Check the log file for the lines shown below, note that you must look for your current Softphone version string, e.g. "release-V5.6".

[FTL|2|_3CXSoftphone.App] UNHANDLED EXCEPTION

System.IO.FileNotFoundException: The specified module could not be found. (0x8007007E)

   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHR(Int32 errorCode)

   at WinRT.ActivationFactory.Get(String typeName)

   at Windows.Media.Playback.MediaPlayer.get__objRef_global__Windows_Media_Playback_MediaPlayer()

   at Windows.Media.Playback.MediaPlayer..ctor()

   at _3CXSoftphone.Telephony.Ringtone.RingtonePlayerImpl..ctor(ILoggerFactory loggerFactory, IAudioDeviceSource audioDeviceSource, ISettingsService settingsService) in C:\_\workspace\3CXPhone\softphone\release-V5.6\app\3CXSoftphone\Telephony\Ringtone\RingtonePlayerImpl.cs:line 31

If this exception is shown then perform the following actions:

  • Click on Start > Run, type optionalfeatures and press OK
  • Select Media Features
  • Expand and ensure that Windows Media Player Legacy (App) is also selected
  • Click the OK button
  • After the process finishes, reboot the PC.
  • In case the above steps do not work and you are still getting the same error, open powershell as an administrator and run the following command:

                

Get-WindowsCapability -online | Where-Object -Property name -like "*media*" | Add-WindowsCapability -Online

  • Reboot the PC.

Softphone starts and terminates immediately

If your Softphone appears to start normally, but then closes immediately, follow the steps below to resolve the issue:

  • As a first step, check Event Viewer:
  • Expand Applications and Service Logs > Microsoft > Windows > AppxDeploymentServer > Microsoft-Windows-AppxDeploymentServer/Operational
  • Check if you see an entry similar to:

        

MicrosoftCorporationII.WinAppRuntime.Singleton_8000.921.1539.0_x64__8wekyb3d8bbwe :

C:\Program Files\WindowsApps\MicrosoftCorporationII.WinAppRuntime.Singleton_8000.921.1539.0_x64__8wekyb3d8bbwe\microsoft.system.package.metadata\S-1-5-21-...-MergedResources-*.pri :

No user-specific merged files found

You can further confirm that this is the exact issue to be resolved using the steps below by:

  • Confirming that launching the Softphone as an administrator works fine;
  • It is specifically standard user sessions that fail.
  • Take a note of your WindowsAppRuntime Singleton version; run the following command in Powershell:

Get-AppxPackage -Name "*WinAppRuntime.Singleton*" | Select-Object Name, Version, PackageFullName

  • Match it to the below table and search Windows App SDK + version on Google and download the Redistributable (ZIP) package from Microsoft:

Singleton Version

Windows App Runtime Version

7000.xxx.xxxx.x

Windows App SDK 1.7

8000.xxx.xxxx.x

Windows App SDK 1.8

  • Extract the ZIP file and navigate to:
  • /{ExtractedFolder}/MSIX/win10-x64
  • Perform the two steps shown below:
  • As an Administrator, copy the Singleton .msix file into your personal Downloads folder and then
  • Run the following command in Powershell with Administrator rights:

For Windows App SDK 1.7

$path = "$env:USERPROFILE\Downloads\Microsoft.WindowsAppRuntime.Singleton.1.7.msix"

Add-AppxProvisionedPackage -Online -PackagePath $path -SkipLicense -LogPath "C:\Temp\Singleton_Provision.log"

For Windows App SDK 1.8

$path = "$env:USERPROFILE\Downloads\Microsoft.WindowsAppRuntime.Singleton.1.8.msix"

Add-AppxProvisionedPackage -Online -PackagePath $path -SkipLicense -LogPath "C:\Temp\Singleton_Provision.log"

  • Once done, relogin into Windows as the user with the Softphone startup issue, and while not not in admin mode, run the following command in powershell:

Add-AppxPackage -RegisterByFamilyName -MainPackage "MicrosoftCorporationII.WinAppRuntime.Singleton_8wekyb3d8bbwe" -Verbose

  • Close and relaunch the 3CX Softphone as the affected user to confirm it now starts normally

See also

Last Updated
This document was last updated on 28 July 2026
https://www.3cx.com/docs/troubleshoot-softphone/