Office 2016 and 2013 users who use run-a-script rules are discovering their scripts are currently disabled (as is Start Application), thanks to a security update. When the update is installed, any existing run-a-script and run application rules will be disabled.

^ that option, ‘start application’ is missing.

The fix is easy, as usual, just a registry key.  :o)

# Outlook 2016
$registryPath = "HKCU:\Software\Microsoft\Office\16.0\Outlook\Security"
$Name = "EnableUnsafeClientMailRules"
$value = "1"
New-ItemProperty -Path $registryPath -Name $name -Value $value`
                 -PropertyType DWORD -Force -Verbose

# Outlook 2013
$registryPath = "HKCU:\Software\Microsoft\Office\15.0\Outlook\Security"
$Name = "EnableUnsafeClientMailRules"
$value = "1"
New-ItemProperty -Path $registryPath -Name $name -Value $value`
                 -PropertyType DWORD -Force -Verbose

Credit: https://www.slipstick.com/outlook/rules/outlook-2016-run-a-script-rules