RecEnv.exe CRecoveryToolAction::NeedsAuthentication

NoAdminPasswordForWinRE.Reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RecoveryEnvironment]
"WinREAuthenticationRequirement"=dword:00000002

So import that registry setting above to the target system.
It'll will avoid that start annoying admin password prompt when you use Windows startup recovery.

Here the decompiled source from RecEnv.exe

int CRecoveryToolAction::NeedsAuthentication(CRecoveryToolAction *this)
{
...
    Size = 4;
    if ( !Utils::GetRecoveryEnvironmentValue(L"WinREAuthenticationRequirement", RRF_RT_REG_DWORD, &OUTVal, &Size) )
    if ( OUTVal == 1 )
    {
      return 1;
    }
    else if ( OUTVal == 2 )
        return 0;

    }
}

LSTATUS     Utils::GetRecoveryEnvironmentValue(LPCWSTR lpValue, DWORD dwFlags, unsigned __int8 *OUTVal, unsigned int *Size)
{
  return RegGetValueW(
           HKEY_LOCAL_MACHINE,
           L"SOFTWARE\\Microsoft\\RecoveryEnvironment",
           lpValue,
           dwFlags,
           &dwFlags,
           OUTVal,
           Size);
}



WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
    CImmersiveRecoveryUi::Run(CImmersiveRecoveryUi *this)
        StartPage = CImmersiveRecoveryUi::GetStartPage(this, &Block, v23);
        v46 = LaunchBootUx(8i64, StartPage, v44);
}

CImmersiveRecoveryUi::GetStartPage(CImmersiveRecoveryUi *this, int *a2, unsigned __int16 *a3)
{
    ...
    if ( CRecoveryEnvironment::IsAuthenticationRequired(*&this->CImmersiveRecoveryUi0)
      && CRecoveryToolAction::NeedsAuthentication(RecoveryToolAction) )
    {
      Retval = 11;
    }
    else
    {
      Retval = 0;
    }
    ...
}