Wiping your Mac and restoring from a backup is a great way to start fresh with a clean install of macOS and your files. This can help improve performance, fix software issues, and remove clutter and old files you no longer need. Here’s a step-by-step guide on how to properly wipe your Mac and restore from a Time Machine or other backup.
Back Up Your Mac
Before wiping your Mac, it’s absolutely essential that you have a full, current backup of all your files. This will allow you to restore your data after the wipe. The best way to back up a Mac is with Time Machine.
Time Machine is included free with macOS and will automatically back up everything on your Mac – documents, photos, music, videos, apps, settings, and more. Here’s how to set up Time Machine:
- Open System Preferences > Time Machine
- Click “Select Backup Disk”
- Choose an external disk to use for backup. This can be a USB drive, Thunderbolt drive, or network storage. The disk must be at least the same size as the storage on your Mac.
- Click “Use Disk”
- Turn Time Machine to “On”
- Time Machine will now regularly back up your entire Mac whenever the drive is connected
Be sure the external backup drive you use has enough space for a full backup. Let Time Machine run regularly until you have a complete, up-to-date backup before wiping your Mac.
How to Wipe a Mac
Once you have a current backup, you can wipe your Mac clean and do a fresh macOS install. Here are the steps:
- Restart your Mac into Recovery Mode:
- Restart your Mac and hold down Command + R as it boots up
- This boots you into Recovery Mode
- Choose Disk Utility from the macOS Utilities window. This will launch Disk Utility.
- Click “View” in the top left and choose “Show All Devices”
- Select your main Mac hard drive volume in the sidebar
- Click the “Erase” button
- Choose “Mac OS Extended (Journaled)” as the format
- Give the volume a name if you want, such as “Macintosh HD”
- Click “Erase” to wipe the drive
- Quit Disk Utility when done
This will completely wipe and reformat the main drive on your Mac, deleting all its files and installing a fresh, blank filesystem. Now you can install a new, clean version of macOS.
Reinstall macOS
With your drive wiped clean, you can now do a fresh install of the macOS operating system:
- From the Recovery window, choose “Reinstall macOS”
- Follow the onscreen prompts to install the latest macOS version compatible with your Mac
- This will install a brand new, clean version of macOS on your wiped drive
Once the macOS installation finishes, your Mac will boot up to a fresh, new desktop with no files or apps installed yet.
Restore Files and Settings from Backup
Now it’s time to restore your files, apps, and settings from your backup. If using Time Machine:
- Open Migration Assistant – you can find this in Finder > Applications > Utilities
- Choose “From a Mac, Time Machine backup, or startup disk”
- Select your Time Machine backup disk
- Click “Continue”
- Migration Assistant will scan the backup and allow you to selectively restore files, applications, user accounts, and settings
- Choose what you want to restore and click “Continue”
- The restore process will begin, transferring your data from the backup to your freshly wiped Mac
For other types of backups, such as cloud backups or drive clones, you may need to restore files manually by copying them over from the backup source.
An Alternative: Internet Recovery
There is another way to wipe your Mac and reinstall macOS, using Internet Recovery. This allows you to download a clean version of macOS over the internet, rather than installing from a local Recovery partition. Here is the Internet Recovery process:
- Restart your Mac and hold down Command + Option + R
- This will boot into Internet Recovery mode
- Use Disk Utility to wipe your drive, just like before
- Choose “Reinstall macOS” from the Utilities window
- The installer will now download the latest macOS over the internet, instead of installing from a local partition
- Follow the prompts to install macOS onto your wiped drive
Internet Recovery can be slower, since it needs to download macOS rather than running it locally. But it ensures you get the absolute latest version. Internet connection is required.
Clean Install macOS Using a Bootable USB Drive
Finally, you can also do a clean macOS install using a bootable macOS installer drive on a USB stick. Here’s how:
- Prepare a USB flash drive that’s at least 12GB in disk space
- Download the macOS installer from the App Store
- Run the installer and follow prompts to create a bootable installer on your flash drive
- Restart Mac and hold down Option key during boot to select the flash drive
- This will boot from the USB to launch the macOS installer
- From there, use Disk Utility to wipe your Mac drive, then install a fresh copy of macOS
The bootable USB method allows you to install macOS without needing an internet connection or external recovery drive.
Essential Steps Before Wiping a Mac
Before wiping your Mac, be sure to:
- Have a full, current backup – Time Machine backup recommended
- Make note of any license keys for purchased software you may have
- Deauthorize any devices connected to Apple services (iTunes, iMessage, etc)
- Sign out of iCloud and Apple ID accounts
- Disconnect external devices besides your backup drive
This will ensure no data is lost and make the transition smoother.
What Exactly Gets Wiped from My Mac?
When wiping and reinstalling macOS, everything gets deleted from your Mac’s drive, including:
- All user files and folders (Documents, Pictures, Music, etc)
- Installed applications and program files
- System files and folders required for macOS to run
- User accounts and settings
- Security certificates
- Cached and temporary files
- Virtual memory files
Essentially, the entire contents of your Mac’s drive get erased. Be absolutely certain you have backups before proceeding!
Benefits of Wiping a Mac
Here are some of the benefits of wiping your Mac drive and doing a fresh macOS install:
- Resolve software issues caused by corrupted files
- Remove pre-installed bloatware that came with your Mac
- Eliminate vulnerabilities and malware
- Improve performance and free up drive space
- Factory reset your machine back to its original state
- Get a fresh start with the latest macOS version
Wiping and reinstalling macOS is one of the best ways to clean and optimize your Mac. Just be sure your data is fully backed up first!
When Should I Wipe My Mac?
Some good times to consider wiping your Mac include:
- Before selling or gifting your Mac to remove personal data
- When you notice performance slowly decreasing over time
- If you suspect your Mac has malware or a virus
- When macOS starts crashing or showing major bugs
- If you can’t resolve a software issue any other way
- When you want to remove unnecessary programs and files
As long as you have a backup, wiping your Mac gives you a fresh start and can extend the useful life of your machine.
How to Backup a Mac Before Wiping It
Backing up your Mac properly before wiping it is crucial. You have a few options for Mac backups:
Time Machine
Time Machine is the built-in backup solution in macOS. It requires an external hard drive but provides automatic, continuous backups of your entire Mac.
Cloud Backup
Services like iCloud, Dropbox, and Google Drive allow you to backup your Mac to the cloud. Only downside is bandwidth limits for large backups.
Clone Drive
Use disk cloning software like Carbon Copy Cloner to create a full duplicate of your Mac drive you can restore from.
Manual Copy
Manually copy important files to an external hard drive or cloud storage as a backup option.
Ideally, use Time Machine along with another backup method like cloud or cloning for redundancy.
How to Restore Apps After Wiping a Mac
After wiping your Mac, you’ll need to reinstall your applications. Here are some tips:
- Check the App Store purchase history to download previously purchased apps
- Use original app installers and license keys to reinstall apps
- Download and reinstall apps from developer websites
- For Office 365, login to your account to download again
- Use Migration Assistant to transfer apps from a Time Machine backup
- Manually reinstall apps from an external clone drive
Make a list of all essential apps you use to reference during reinstallation.
How to Restore Settings After Wiping a Mac
To restore settings after wiping your Mac:
- Sign into iCloud to sync settings across devices
- Use Migration Assistant to transfer settings from a Time Machine backup
- Manually restore settings by reconfiguring each app individually
- Sign back into mail accounts, websites, WiFi networks, etc
- Tweak System Preferences to get visual settings like desktop back
Expect settings restoration to be time consuming – automating it as much as possible via Migration Assistant or iCloud helps.
How to Restore Files After Wiping a Mac
To restore your personal files after wiping your Mac:
- Use Migration Assistant to transfer from a Time Machine backup
- Connect external clone drive and copy files back manually
- Sign into cloud backup services (Dropbox, Google Drive, etc) to sync files
- For media, reconnect to iTunes/Photos to re-download
- Copy files from a Windows PC backup or another Mac
- Use Mac’s Restore function if you have a Deja Vu backup
If using Time Machine, you can selectively restore files and folders during Migration Assistant.
Potential Issues When Wiping a Mac
Some potential issues to be aware of when wiping your Mac include:
- Loss of data if no backup – backup first!
- Inability to restore data from backup later
- Discovery some apps are no longer supported
- Difficulty recreating complex custom settings
- Latest macOS version may not work on older hardware
- Need to repurchase some software licenses
- Restoring files from Time Machine backup could take hours
Carefully check compatibility and prepare accordingly before wiping your Mac to avoid issues.
Tips for Restoring Data After Wiping a Mac
Follow these tips for smoothly restoring your data after wiping your Mac:
- Use Migration Assistant for automatic transfer from Time Machine backups
- Have a checklist of all apps, files, and settings to restore
- Reconnect accounts and services in order of priority
- Don’t restore old data you no longer need – start fresh
- Expect restoring settings and customizations to take time
- Work in batches restoring data rather than all at once
- Check licenses and re-purchase apps no longer supported
Stay organized, have backups ready, and follow a plan to make restoring data simple after wiping your Mac.
FAQs About Wiping a Mac
Is wiping a Mac necessary?
Wiping a Mac is not strictly necessary but recommended to periodically refresh performance by starting from scratch. It can fix a variety of issues caused by bloated caches, outdated settings, fragmented files, and corrupted data.
Will wiping delete my data?
Yes, wiping a Mac completely erases all data, programs, and user files on the drive. Be absolutely certain to have backups before wiping your Mac.
How do I wipe a Mac before selling it?
Before selling your Mac, wipe it by booting into Recovery mode, launch Disk Utility, select the drive, and click “Erase” to permanently delete all contents from the drive.
Can I restore from Time Machine after wiping?
Yes, you can fully restore your files, settings, and apps from a Time Machine backup onto your freshly wiped Mac using the Migration Assistant tool.
How long does wiping a Mac take?
It only takes a few minutes to wipe the drive itself using Disk Utility in Recovery mode. But fully reinstalling macOS and all your apps can take hours.
Is it better to wipe Mac or reinstall macOS?
Wiping your Mac drive provides a cleaner, fresher install of macOS vs just reinstalling macOS over itself. But both are good options.
What will I lose if I wipe my Mac?
Wiping a Mac deletes all user files, apps, accounts, settings, caches, personalizations, and other data. Be sure to backup everything important first.
Can I choose what to delete when wiping Mac?
No, disk wiping will delete the entire contents of the chosen drive indiscriminately. You cannot selectively choose what gets erased.
How do I know if wipe is successful?
After wiping the Mac drive, the storage space should show it is empty/available. Reboot and confirm macOS needs to be reinstalled to verify.
Conclusion
Wiping your Mac and reinstalling macOS is an excellent troubleshooting step to refresh performance and start from scratch. Just be absolutely sure to have a complete backup using Time Machine before proceeding. Wipe the drive using Disk Utility, reinstall a clean macOS, then selectively restore apps, settings, and data from backup. With some diligence, you can wipe your Mac and restore it to a like-new state.