Pinpoint problems using Activity Monitor
1 Open Activity Monitor
Activity Monitor is included with macOS. It’s in Utilities in the Applications folder. The quickest way to open it is using Spotlight: press ç+[ spacebar], start typing ‘activity’ and when the app is listed, select it and press ® .
2 See what’s going on
All the currently running processes are listed at the left. Some of these are app names that you’ll recognise (with their icons), others are system functions that you won’t. To see only apps, choose View > Windowed Processes.
3 Check resource usage
The tabs across the top show which processes are using which resources. If the hard disk is constantly chuntering, for example, see Disk. Click the Process Name column to alphabetise processes, or another to rank by usage.
4 It’s down to CPU
To check what’s slowing down your Mac right now, click the CPU tab and rank by % CPU. If ‘nsurlstoraged’ turns out to be a busy little bee, that’s Safari. Close any pages you don’t need open, or quit Safari, and see the percentage fall.
5 All systems go
Don’t be surprised that obscure system processes use resources, but if one seems excessive, search Google for its name to get tips. Processes beginning ‘md’ (for ‘metadata’) relate to Spotlight activity. Consider limiting it (see page 28).
6 Kernel blip
If ‘kernel_task’ is using a lot of CPU, it may be managing the processor to stop it overheating under load. If no other processes are using much CPU, reset the SMC (see page 24). If it still happens, there could be a hardware fault.