iMac 10.13.3系统重启或关机卡顿故障求助

Hey there, sorry to hear you're stuck with this frustrating shutdown hang and failed update problem—let's work through actionable steps to get this sorted:

• First, complete the update in Safe Mode
  Third-party startup items or kernel extensions are often the hidden culprit behind shutdown hangs and stuck updates. Here's how to test this:

  1. Restart your iMac, hold down the Shift key until you see the login window
  2. Log in, then re-launch Software Update and attempt to install the supplemental update again
     Safe Mode disables all non-Apple extensions, which should let the update finish without triggering the shutdown hang.

• Clear corrupted update caches
  Damaged update files can cause installation loops and cascading shutdown issues. Use SSH or a local Terminal to run this command:

  sudo rm -rf /Library/Updates/*
  

  After deleting the cache, restart your Mac, re-download the update, and test both the installation and shutdown process.

• Check for problematic third-party kernel extensions
  SSH into your Mac and run this command to list all loaded non-Apple kernel extensions:

  kextstat | grep -v com.apple
  

  Look for extensions from tools like third-party antivirus software, custom disk utilities, or hardware drivers. Uninstall the associated apps temporarily, then test if shutdown and updates work normally.

• Reset the SMC (System Management Controller)
  For Intel-based iMacs, resetting the SMC fixes many power-related glitches:

  1. Force shut down your iMac (hold the power button if needed)
  2. Unplug the power cord, wait 15 seconds
  3. Plug the cord back in, wait 5 seconds
  4. Press the power button to boot up

• Test with a new admin account
  Corrupted user preferences can sometimes cause odd system behavior. Create a fresh admin account to rule this out:

  1. Go to System Preferences > Users & Groups
  2. Unlock the pane, click the "+" button to add a new admin account
  3. Log into this new account, then try installing the update and shutting down

If none of these steps resolve the issue, restoring from a Time Machine backup (from before you attempted the update) is a reliable fallback, or you can reach out to Apple Support for deeper diagnostics.

内容的提问来源于stack exchange，提问作者Mark Robinson