All of a sudden, I can't add a hot key anymore.
I'm not sure what happened, but when the "Type" field is grey in the "This Hot Key" section, it won't accept ANY kind of input.
Key capture still functions perfectly.
I've had Karabiner Elements installed for a while without trouble, but I figured I'd uninstall it to see -> no joy
I have an external keyboard on my laptop, I've turned it on/off/on still no joy.
When I try typing a trigger, the "live event" (keyboard and emoji viewer) shows that the keys are registered - they just don' get too KM.
I had the same problem. It resolved when I turned off the access for KM in System Preferences then back on again. No idea why it worked but it did. Might be worth a try.
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, selecting menus, copy/paste, etc), you need to toggle the accessibility permissions (System Preferences, Security & Privacy, Privacy, Accessibility) for Keyboard Maestro and Keyboard Maestro Engine off and then on again.
This is a bug in Mojave’s accessibility upgrade process - the worst part is that the system lies and tells Keyboard Maestro that Keyboard Maestro has accessibility permissions, but then fails the operations, so Keyboard Maestro cannot alert you to the missing permissions.
I'm sorry you guys are having issues with KM and Mojave. Mojave can be a real PITA.
But if you follow @peternlewis' instructions you should be fine.
Just so you know that KM can work with Mojave, I just setup a new iMac that came with Mojave, and migrated all my apps, including KM. After making the required changes in System Preferences, KM is working fine.
I just tried assigning a hotkey trigger to both an existing and a new Macro, and it worked fine with both.
Running Keyboard Maestro 8.2.4 on macOS 10.14.5.
Good luck to all, and hang in there. KM is definitely worth the trouble brought on my Mojave.