I upgraded to OS X El Capitan a few days ago and was having issues with reboot and shutdown times. It could take up to a minute. So I cloned back OS X Yosemite from a backup and partitioned part of my SSD and installed OS X El Capitan to troubleshoot. Even on the partition OS X El Capitan still shuts down and reboots slowly. When it finally gets to the Apple logo it boots up fast.

Not that big of a deal, just was curious what was going on. OS X Yosemite works fine with no lag in reboot and shutdowns.


I have two boot volumes listed, El Cap that's on a partition, and Yosemite. I select the El Cap partition and it boots fine into El Cap after the restart. and when I'm completely shutdown and boot onto El Cap it boots fine, no lag. Its when I'm booted up into El Cap and do a restart or shutdown. That's where the lag is. I tried Verbose mode and when it started up, it did the white text on the screen then booted normally. I really don't know what I'm looking for here.

  • I always do clean upgrades between major releases so I can't comment specifically on something that occurs during a major upgrade however you might want to have a look at How to Reset NVRAM on your Mac and Reset the System Management Controller (SMC) on your Mac to see if either will help. It did for me when my system had slowed down to a reboot taking three times as long as it used to. – user3439894 Jul 10 '16 at 15:24
  • Resetting your SMC might help. – Jordan Baron Jul 10 '16 at 20:29
  • Thanks for the reply. I've tried it both ways. Update from Yosemite and erase disk and do a fresh install. – Jake Jul 10 '16 at 21:12
  • I have tried this also but it didn't help. To be more clear, for instance, when I choose restart from the Apple menu, holding option so I don't get the warning window, thats when the lag time starts. It sits there with the spinning indicator for awhile then the screen goes black and sleep mode starts on my monitor. Then about 20-30 more seconds I get the Chime. After the Chime it boots really quick. – Jake Jul 10 '16 at 21:13

Here are few suggestions to troubleshoot the slow reboot issue:

  • After the system is booted, run:

    sudo dmesg | less
    

    and check for any errors.

  • Start up your Mac in safe mode (hold Shift after restart).

  • Start up your Mac in single-user mode (CMD-S) or verbose mode ( CMD-V).
  • Check for any suspicious messages in /var/log/system.log file during boot time. Or use the Console.app to check the logs during boot time.
  • Check the health of your battery using an app.
  • If you got any system crashes, please check for any shutdown causes.
  • Disable non-Apple kernel extensions (check by kextstat | grep -v com.apple).
  • Disable non-Apple services at startup (check by launchctl list | grep -v com.apple).
  • Make sure you don't use any custom boot arguments (check by nvram boot-args).
  • You can consider booting in verbose mode by: sudo nvram boot-args="-v".
  • Run Apple Hardware Test on your Mac (hold the D key during on reboot).
  • Book an appointment at Genius Bar and ask them to run the full hardware test using their macOS NetBoot Triage Image.

If you get out a stopwatch, you can break down the various items.

  1. Boot holding option down - isolate the SMC pointing to the startup volume
  2. Select the boot image and press return to time things - test the OS starting without the user portion
  3. Turn off automatic log in - isolate the user part of startup

After about three starts, you should have a nice table of the timings and can then ask a follow on question on how to fix one or more than one of the items above. The fix for each is different and you may not need any if you get repeatable startup times and it's due to actual work being done. Hard to know without some hard numbers.

Make sure that the default boot volume is your boot drive (System Preferences -> Start Up Disk -> Select(Highlight) Boot Drive)

Also, boot up with Cmd+v (Verbose). You will see more information and get an idea whats holding up the boot process.

  • Thanks for the replies. I have two boot volumes listed, El Cap thats on a partition, and Yosemite. I select the El Cap partition and it boots fine into El Cap after restart. and when I'm completely shutdown and boot onto El Cap it boots fine, no lag. Its when I'm booted up into El Cap and do a restart or shutdown. That's where the lag is. I tried Verbose mode and when it started up, it did the white text on the screen then booted normally. I really don't know what I'm looking for here. – Jake Jul 11 '16 at 12:01

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