One of my favorite macros which I have used for many years in Apple Mail is this:
Select All
Move to Junk
Very simple but very effective.
After upgrading to Mojave on my iMac 27 a confusing behavior started. The first step, Select All, does not work any more but the second step, Send to Junk, works. Furthermore, if I try to write a new macro and select the action ”Type a Keystroke” I can’t enter the keystroke any more. Nothing happens. However, other existing macros work as they should.
In order to figure out the problem I tried the same thing on my MacBook Pro 13 with Mojave and there it all works.
You will have to ensure you enable Accessibility for both Keyboard Maestro and Keyboard Maestro Engine. If you have any troubles with accessibility (eg typing keystrokes), toggle the accessibility permissions for Keyboard Maestro and Keyboard Maestro Engine off and then on again.
I took the Keyboard Maestro folder from Super Duper backup from Library > App Support and toggled the System Pref checkmarks off and on for that and Keyboard Maestro and still no shortcuts.