Boot time or Startup performance score extension attributes

macOS does not have a built-in "boot time duration" or "startup performance score" metric.

Unlike Windows (which logs boot duration in Event Viewer as Event ID 100), macOS does not record how many seconds it takes from power-on to usable desktop. The Unified Logging system records startup events but not boot duration.

What you CAN collect via EA:

• Last boot timestamp (sysctl kern.boottime) - when the system booted
• Uptime - how long since last boot

What you CANNOT natively collect:

• Actual boot duration in seconds (power-on to login screen)
• Startup performance score

Workaround (limited): Create a Startup Policy that writes a timestamp to a file, then calculate the difference from kern.boottime. However, this only measures time after kernel initialization — it cannot measure firmware/bootloader phases.

There is no Apple documentation for a native boot duration metric because this feature does not exist in macOS.

Hi ​@Ilya ,

This option can be used if you want to estimate how long a Mac takes to restart until the startup process is completed.

By using the ~ $ last reboot command, you can see the timestamps of reboot and shutdown events, which allows you to roughly infer the restart duration when a Restart action is performed.

However, this method is Not suitable if the Mac is fully shut down and powered on again at a later time, as ~ $ last reboot does not accurately represent the actual startup duration in that scenario.