Crazy bug that locks CMD+Tab and mouse clicks

[carlsson]

Recently I have stumbled upon a bug that seems really hard to track down:
Intermittently, CMD+Tab doesn't work, nor can I use the mouse to click on things. I am able to switch applications other ways (via Spotlight or Keyboard Maestro shortcuts), and everything else seems to work.
After a period of time, maybe 20 to 40 seconds, it all works again, and the CMD+Tabs I have done now takes actions.
If I during this period looks what takes CPU I can't see nothing strange, and I really can't see what's causing this.

This is of course extremely annoying! How can I troubleshoot this without reinstalling everything?

It started a month or so ago.

Ideas are welcome. 🤔

 

[BadMacRumours]

Try closing each of your applications one-by-one until you find the culprit I suppose.

 

[carlsson]

Good start. Since I have limited time when it happens, it might be hard to do it in time. But still, good start – Thanks for the input!

 

[Stefdar]

Good start. Since I have limited time when it happens, it might be hard to do it in time. But still, good start – Thanks for the input!

Are you using any third party app like BetterTouchTool?

 

[carlsson]

Not that much, but some:
- BetterSnapTool
- Focus
- KeyBoard Maestro
- Adobe CS
- OmniFocus
- Drafts
- ScanSnap
- CleanMyMac

I think that's it.

 

[Tozovac]

No answer yet?

 

[carlsson]

None yet. It happens intermittently, and when it does i am just too slow to shut down my background processes.

At least I think it has to be one of these background processes:
- WatchGuard Mobile VPN
- Network VPN
- BetterSnapTool
- Focus
- KeyBoard Maestro
- Adobe CS
- ScanSnap
- CleanMyMac
- Drafts

 

[svenmany]

KeyBoard Maestro seems a likely culprit.

An application blocked on something (say, a response from the network) would not consume any CPU resources.