Suddenly the "Start Screen Saver" Action Doesn't Work Anymore

I have a simple macro which just starts the screen saver (so that I can trigger the screen saver with a custom keyboard shortcut).

This worked for years without trouble. Now I have changed my screensaver from "Message" to "Photos" and the macro (both via shortcut and via run button in Keyboard Maestro) has stopped working. It just does nothing. No error or anything.

Though the strangest thing is that the system trigger via mouse "Hot Corners" still works: I move my mouse to the right lower corner (which I have set to screensaver) - and the screen saver starts!

Any idea how to fix this - or at least how to trouble shoot it?

Many thanks for any pointers,

It works for me (however I'm running Monterey not Big Sur).

Are you running other apps, especially utilities? Did you try closing all of them? Did you try booting into macOS safe mode?

When was the last time you rebooted? Rebooting solves 50% of all problems the world has ever encountered.

So does changing it back to ”Message” cause the macro to work again?

Worked for me for a looong time too. I'm running Mojave.

Nothing new installed, but i will try to eliminate culprits..

Have rebooted straight when this occurred. But it is still happening.

Very strange that the Hot Corner still works...

"Eliminating culprits" should be really easy if you try my idea of booting into safe mode. If the problem disappears immediately upon booting in safe mode, then you have a strong indicator where the problem lies.

Finally I managed to boot into safe mode - and the Picture Screensaver still gives me the problem.

For now I wrote macro which moves the mouse into a corner and this does still activate the Picture Screensaver. Not totally reliable but good enough.

At some stage I will upgrade to Catalina hoping than the issue will go away.

I just came to this problem after system preference prompts me to upgrade the studio display and it kills the shortcut right after I upgraded successfully. if I guess right it's time for Keyboard Maestro to upgrade its software to cope with the news Apple upgrade =="