Fixing startup issues & reinstalling macOS

Resetting the SMC & PRAM

Trouble with powering up, computer shutting down unexpectedly or fans running constantly? Try resetting the System Management Controller. If you have a laptop, plug in the power cord. Note these instructions are for Intel-based Macs. If your Mac has Apple Silicon, simply restart your computer to reset the SMC.

  1. Shut down the computer.
  2. For a laptop: Press and hold the power button for 10 seconds and release. Then on the built-in keyboard press Control & Option keys on the left side and Shift key on right side for 7 seconds. Then keep holding those keys and press the power button for another 7 seconds. If the computer is on it will shut off.
  3. For a desktop: unplug the power cord from the back of the computer. Wait 15 seconds, then plug back in.
  4. On either laptop or desktop: Get ready… in a moment you’re going to press 4 keys: Command-Option-P-R.
  5. Press & release the power button, then within 1 second press those 4 keys. Hold them for 15 seconds as the computer starts. It might help to have one person hold the keys and the other hit the power button.
  6. Release the keys and sign into your desktop.

Repairing the startup disk

Sometimes the computer has trouble finding files it needs on the startup drive. You can often repair this with the Disk Utility.

  1. Hold the Command and R keys as you start the computer. Keep holding until you see the gray Apple logo.
  2. Click Disk Utility.
  3. Select your startup disk in the left column. It’s usually named something like Macintosh HD.
  4. Click First Aid near the top of the window, then click Repair Disk in the lower-right corner.
  5. When the disk repair is complete, click the Apple menu and Restart. If the disk cannot be repaired, contact us for help.

Restoring from a Snapshot or backup

Still having trouble? Modern Macs have a function called Snapshots. Before any major upgrade and at other times, the system saves the state of all your files. You might reset things to a working state, from before the problem began. Another useful tool is Time Machine backups, which copy your files to another drive or server.

One catch: you could lose anything you changed on your computer’s drive since the snapshot or backup was made. Files synced with iCloud, Dropbox, Google Drive or a server (like email) are safe – they’re updated with the latest version after restoring. If this approach isn’t feasible, skip to Reinstalling macOS below.

  1. Plug in the power cord.
  2. Hold the Command and R keys as you start the computer. Keep holding until you see the gray Apple logo.
  3. Click Restore from Time Machine backup. You can try this even if you don’t actually have Time Machine configured (but it helps).
  4. Select your startup hard drive (usually Macintosh HD), then continue.
  5. Choose a Snapshot – they’re listed by date and time. Often the most-recent Snapshot is best, or pick one from just before the issues started.
  6. No snapshots? Try selecting a backup drive instead, then choose a recent backup.
  7. Click Continue and confirm you’re ready to restore from the snapshot or backup. If asked to select a destination drive, choose your Macintosh HD in most cases.
  8. Restoring from a Snapshot takes just a few minutes. Restoring from a backup can take several hours. Do not interrupt this process.
  9. The computer restarts. Sign into your desktop as usual.

Reinstalling macOS

If a computer still won’t start and restoring from a Snapshot or backup are out, you may need to reinstall macOS. This does not remove any of your apps or files, just the software that runs the computer.

  1. Plug in the power cord.
  2. Restart while holding the Command-Option and R keys until you see the globe menu. You may need to connect to your wi-fi network or attach a cable.
  3. Click Reinstall macOS.
  4. Follow the instructions on the screen.

For more help, contact Creative Tech Support.

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