For some reason that I don't understand, I occasionally/accidentally start multiple copies of KM at the same time. If I edit a macro in one window, and close it, the changes I make are saved. But then when I close the other window, it overwrites those changes with the earlier version of my macro and I've lost my edits. Today I lost 5 hours of work this way. (I wrote a macro that sets up a chess board and loads/saves the pieces from/to a file using FEN notation.)
Is there some way of preventing two copies of KM from running at the same time? Or is there some other way to prevent overwriting macros that are newer? Or is there some way to recover the overwritten macro?
I'm not particularly upset as I love to program in KM and am always rewriting my code anyway.
I did find a 2018 forum post about this, but the cause seemed to relate to syncing, which I don't do.
As a general rule, Mac OS will not let you launch a second copy of Keyboard Maestro unless you have more than one copy of the application installed.
So find all the copies of Keyboard Maestro.app on your Mac and delete all but one of them. Including emptying the trash.
If you don't have more than one copy of the app, then you need to look at how you are launching them, since the normal mechanisms should never launch a second copy of the same application.
Note that having two editor windows open within a single Keyboard Maestro editor application is fine, that will not cause data loss. Having two editor application instances open definitely will.
Thanks, that's helpful. So I'm guessing that in my case the second copy was located in my Downloads folder, and I'm also guessing that the application bar at the bottom of the screen, which now stores "most recently used programs" may have included a link to Keyboard Maestro.app in that section. That's possibly how I got two concurrent copies running.