After Outlook updated, the mail rules' Run Script option is missing

Outlook 2013 on Windows 8.1 got updated today. Since then, the Run Script option as an action for incoming mails is missing, plain not there any longer.

All incoming messages and RSS feeds are directed to VBA scripts.

I can access the scripts via Alt+F11: they are still there.

The affected rules are in red writing, contain an (Error) text, and attempting to modify them results in a message box stating that the rule can not be modified in the current mode.

Via Options, Trust Center, Settings, Macro settings, the option to activate all macros is selected.

How do I re-enable processment of my scripts? Some new registry entry?

Solution 1:

Just add the EnableUnsafeClientMailRules value of 1 (DWORD) to HKEY_CURRENT_USER\Software\Microsoft\Office\<version>\Outlook\Security registry key to enable "run a script" action. After that, restart Outlook.

<version> is 16.0 for Outlook 2016, 15.0 for Outlook 2013, 14.0 for Outlook 2010.