/AddDefaultApps

Add Custom Apps to Default Apps in Windows

Add custom programs to defaults apps settings page in Windows

To add Windows Explorer, you need trustedinstaller privilege, open Powershell as admin:

Set-ExecutionPolicy Unrestricted CurrentUser;Set-ExecutionPolicy Unrestricted LocalMachine;install-module ntobjectmanager -Force;sc.exe start trustedinstaller;$p = Get-NtProcess TrustedInstaller.exe;

Create Command Prompt with trustedinstaller privilege

import-module ntobjectmanager;sc.exe start trustedinstaller;$p = Get-NtProcess TrustedInstaller.exe;$proc = New-Win32Process commend.exe -CreationFlags NewConsole -ParentProcess $p

In the Command Prompt window, type

regedit /s <path>\Explorer.reg

Now you can make Explorer open .rar, .bz2, .7z, etc. If you had set 7-Zip or WinRAR as the default opener, you can undo the changes.