What Happens When You Restore a Drive on Mac
Restoring a drive on a Mac essentially wipes the drive completely and reformats it. The Disk Utility app contains a Restore function that erases all of the existing content on the selected drive and reformats it. This restore process does not save or transfer any of the data that was on the drive prior to restoring it. Everything is erased.
When you restore a drive, the Mac’s Disk Utility erases the drive’s file system, partitions, and all its data. It reformats the drive, writing a new, empty file system to the drive. This makes the disk appear as if it is completely brand new. Once restored, the drive will show its full capacity available as if no data is stored on it.
In summary, restoring an external hard drive on a Mac completely wipes the drive and restores it to a blank, unformatted state. The restore function does not migrate or preserve any existing data or files on the drive. The restore provides a way to quickly erase and reformat an external drive.
Why Restore an External Hard Drive?
There are a few key reasons you may want to restore an external hard drive on your Mac:
To fix corruption or errors – If your external drive is experiencing problems like file corruption, mounting issues, or strange behaviors, restoring it can wipe the slate clean and resolve these problems. Restoring deletes all data and reformats the drive, essentially resetting it to factory settings.
Erase sensitive data before selling/giving away – Restoring is a quick and thorough way to erase all your personal or sensitive files before getting rid of a drive. This prevents your data from falling into the wrong hands.
Clear out old data – If your drive is cluttered with outdated or unneeded files, restoring it removes everything and gives you a fresh start. This can help optimize performance.
According to Apple Support, restoring is recommended if your disk needs to be reformatted or erased entirely before it can be used again. It wipes the drive and reformats it for a clean slate.
Back Up Important Data First
Before restoring your external hard drive on a Mac, it’s crucial to back up any important files, documents, or data you want to keep. The restore process will wipe the drive and revert it to a clean, factory-state. This means everything currently on the drive will be deleted.
The best way to back up a Mac is to use Apple’s built-in Time Machine software. Time Machine automatically backs up all your files, apps, settings, and the entire operating system. To set it up, connect an external hard drive that’s at least the same capacity as your internal drive. Then go to System Preferences > Time Machine and select the external drive as the backup disk. Time Machine will regularly back up your Mac whenever the drive is connected.
If you don’t want to use Time Machine, you can manually drag-and-drop important files and folders to an external drive to back them up. Online backup services like iCloud, Dropbox, or Google Drive are another option. Just make sure your files are fully backed up before restoring your external hard drive.
Backing up beforehand protects you from permanent data loss. Don’t skip this crucial step!
How to Restore an External Drive on Mac
Restoring an external drive on a Mac is a straightforward process using the built-in Disk Utility app. Here is a step-by-step guide:
- Connect the external drive you want to restore to your Mac.
- Open the Disk Utility app on your Mac (located in Applications > Utilities).
- In the sidebar, select the external drive volume you want to restore.
- Click the “Restore” button in the toolbar.
- Disk Utility will prompt you to confirm restoring the disk – click “Restore” to continue.
- Select a destination to restore the disk to. This can be the same original disk or a new one.
- Make sure to back up any important data first as restoring will erase the disk.
- Click “Restore” and the process will format the disk and copy the data over.
- Once completed, you can use the restored disk again.
For more details, refer to Apple’s support guide on restoring a disk using Disk Utility.
Alternative Restore Methods
In addition to using Disk Utility, there are a couple alternative methods for restoring an external drive on Mac:
Using Terminal – For more advanced users, you can restore a drive using Terminal commands instead of the Disk Utility GUI. The diskutil command lets you erase, format, and restore volumes. Just be very careful, as typing the wrong command could result in data loss. See Apple’s support guide for the proper Terminal restore syntax.
Third-party software – There are also third-party utilities you can download to restore external drives, like Stellar Data Recovery and iBoysoft Data Recovery. These give you more options and flexibility compared to Disk Utility. However, they are paid software. The free Disk Drill app also includes drive restore capabilities.
What Gets Removed During a Restore
When you restore an external hard drive on a Mac, it completely wipes the drive and resets it to a clean, factory-like state. This process removes all of the following from the drive:
- Personal files such as documents, photos, music, and videos
- Installed applications and programs
- Operating system files and system settings
- Any custom configurations and preferences
Essentially, restoring an external drive erases everything on the drive and returns it to how it was when first purchased. The drive is left blank and empty after a restore.
This is why it’s critical to always back up your data before performing a restore, so you don’t permanently lose your files. The restore process cannot be undone.
Some data recovery software like Disk Drill and Recuva may be able to recover deleted files after a restore, but this is not guaranteed. The most reliable way to protect your data is to always maintain a current backup.
Choosing a File System
When restoring an external drive on a Mac, you’ll need to choose a file system. The two main options are APFS (Apple File System) and Mac OS Extended (HFS+).
APFS is the newer Apple-designed file system that debuted in macOS High Sierra. It includes features like strong encryption, space sharing, snapshots, fast directory sizing, and improved file system fundamentals. APFS is optimized for solid state drives. According to this MakeUseOf article, APFS is a good choice for external SSD drives if you want speed, better storage space management, and error-free backups.
Mac OS Extended (HFS+) is the older file system that was used prior to APFS. It supports drives up to 2TB and stores information in a hierarchical structure. HFS+ works well with magnetic hard disk drives. As noted in the MakeUseOf article, it’s a good option for large external HDD drives, especially if you plan to share the drive between Mac and Windows computers.
You can also choose to encrypt the external drive when restoring it. Encryption adds a layer of security that prevents unauthorized access to your data. However, encrypted drives may have slower performance. Consider whether you need encryption based on the type of data you plan to store.
Ultimately, choose APFS for external SSDs, HFS+ for larger HDDs, and enable encryption if you need the extra security. Select the right file system based on your storage device type, planned usage, and performance needs.
When Not to Restore a Drive
Restoring a drive can be useful for wiping a drive clean and starting over. However, there are some cases where restoring a drive may not be the best option:
If the drive has a hardware failure – If the drive is failing physically, restoring it will not fix underlying hardware issues. It’s better to replace the damaged drive.
If corruption is limited – If only certain files or folders are corrupted, restoring the entire drive is overkill. It’s better to try selective file recovery methods instead.
To explore other troubleshooting options first – Restoring should be a last resort after trying other options like Disk Utility’s First Aid to repair filesystem errors.
When time-sensitive files need recovery – Restoring will wipe all data, so it’s a bad option if you need to urgently recover a specific important file.
In summary, restoring an external drive can wipe your data and should be avoided unless drive failure or corruption is severe. Try less destructive troubleshooting steps first before taking the plunge to completely restore a drive.
FAQs
Here are answers to some frequently asked questions about restoring external hard drives on Mac:
Is data erased when restoring a drive?
Yes, restoring a drive will erase all data currently on the drive. Be sure to back up any important files before restoring the drive (Apple Support).
Can you restore an external drive to factory settings?
Yes, Disk Utility’s restore function allows you to wipe the drive and restore it to its original out-of-box state. This will remove any data, partitions, or file systems currently on the drive.
How long does it take to restore an external hard drive?
Restore times vary depending on the drive’s capacity and connection type. For example, restoring a 1TB drive over USB 3.0 can take 1-2 hours. Restores tend to be faster over Thunderbolt than USB.
Can you restore a drive and keep files?
No, restoring a drive erases all data. You’ll need to back up files separately before restoring if you wish to keep them.
Does restoring fix a corrupted external drive?
Restoring can potentially fix drive corruption issues, but first try repairing the disk using Disk Utility’s First Aid feature. Restoring should be a last resort.
Summary
In summary, restoring an external hard drive on a Mac essentially erases all data and reformats the drive. This can fix corruption issues and wipe a drive clean before selling or disposing of it. However, restoring deletes all files, so be absolutely certain to back up any important data first. Use Disk Utility’s restore function or target disk mode to complete the process. Remember that restoring changes the file system format, which may cause issues if you need to access the drive from a Windows PC. Only restore as a last resort when drive errors can’t be fixed with repair tools. Be sure to double check for any missing files after restoring a drive. With the proper precautions, restoring an external drive can often get it working again or allow you to reuse it.