Good morning...
I have been a KM user for years, so the following surprises me...every day for the last few weeks, when I wake my MacBookPro in the morning, KM is so slow it's unusable. I notice this most when using text replacement (which I use a lot). Restarting KM doesn't fix it. I have to reboot. So I have to reboot every morning.
Any thoughts on causes or fixes?
Many thanks, Gregg
Hey there! Just to clarify, do you mean restarting the KM Editor, or the KM Engine?
I had a similar issue years ago. It may not be your issue but my problem, identified by a spindump, was a corrupted login file. I was informed to delete everything out of my login items (system preferences) and then add any needed startup items back one at a time.
Since I made this modification, I haven’t had an issue. If there is something that you just installed, remove it from the login and reboot. Otherwise, try the first solution. Remember to take a screenshot of your login items screen, first, so you what to place back.
If this doesn’t work, disregard. 
Good luck,
KC
Hey @cdthomer ...I have to confess I don't know the difference between KM Editor and KM Engine. I go into the Dock, right click to close, then reopen. I never thought to look, but it says KM Editor on the icon when I right click. How do you restart the KM Engine???
Thanks, Gregg
Hey, @kcwhat...that's a great idea, thanks for the suggestion!
The Editor is the window where you edit your macros.
The Engine is the mechanism that executes the macros... it is not user accessible, but you can quit the Engine to prevent macros from executing but still have the Editor open to work on them.
Sometimes restarting the engine can help if macros are running slow or otherwise failing. To do so, either click File in the menu bar, then click Quit Engine, then click File again and click Launch Engine.
For more information on the Engine, see this page under the Keyboard Maestro Engine subheading.
If I can't solve my own problem I can't solve yours, but I recommend that you check the size of your KM macro storage file, and also check the amount of RAM that your KM Editor and KM Engine are consuming. I would post instructions on how to do these things, but I should be making breakfast right now.
Today my KM Editor app is using 422 MB of virtual memory and my KM Engine is using up only 244 MB of virtual memory. I don't know what's normal for most people, but this feels very high to me. And when either of these numbers reaches 1 GB, the KM editor becomes so slow I can't use it. So I prevent the problem by restarting them often. I've been dealing with this for well over 5 years, and I've posted here about it, but it has never been solved. So I live with it. It used to happen hourly but since I've stopped putting huge images into Find Image action, the problem is much less frequent now.
The plist file size and the Found Image well usage was going to be my next information request.
@cdthomer...I never saw that before! Just tried quitting and relaunching engine, and it brought instant relief. Thank you!
Where do I find these?
Great! Glad that helped! Every so often I too have to restart the Engine because it starts lagging for whatever reason.