When you sell or donate a Mac or give it to a family member, it’s best to make a clean break: wipe the puppy clean, reinstall the latest version of OS X, and hand off a system that you’re not worried has remnants of yourself on it.
But how can you be sure? Readers have written in with several related questions, so let’s talk this week about erasing a drive, how FileVault 2 encryption can play into it, and out-of-date Recovery Drive partitions.
The safest way to reboot your Mac is via the Apple menu. Click the 'Apple' logo in the top-left corner of your screen and select 'Restart.' If you have windows or apps open that you want to reopen when the computer reboots, place a check mark in the 'Reopen Windows When Logging Back In' check box. Everything is a freeware Control Panel designed to help you manage your SCSI bus(es) and the devices such as hard disks you have connected to it.
Erase and leave no trace
Get Stellar Phoenix Mac Data Recovery and install the program on your Mac.; Launch the app and click 'Start New Scan' to get started. Select a scanning method. In this case, click 'Search Lost/Deleted Volumes' and hit 'Start Scan' to continue.
Reader Jim Kay, who asked about migrating from one Mac to another a couple of weeks ago, had a second question as well that opens a delightful can of worms:
Mail Support. All the topics, resources, and contact options you need for the Mail app on your iOS devices and Mac. Everything is a search utility that locates files and folders by filename instantly on the Windows OS. But, unlike Windows’ search function, Everything will initially displays every file and folder on your computer. Everything can rapidly locate any files and folders by name on an NTFS volume.
Since I’m looking to resell my current Mac, how do I reinstall OS X, so as to wipe my hard drive and resell knowing the new buyer has a cleaned-up computer, and my files are nowhere to be found on it?
Wiping or erasing a drive has a surprising number of definitions. In the olden days, in the long ago, we ran utility software that often came from third parties, which would simply delete the catalog and related records. Such an erase was, in practice, the best way to create a clean installation. But it doesn’t make all the files on the disk unrecoverable—it just makes them harder to retrieve.
To get rid of old data in a thorough fashion, you need use a multi-pass approach, in which every bit of storage in the disk is overwritten with new data (often zeroes). That’s been built into Apple’s Disk Utility for years. When you select a volume in Disk Utility and then the Erase tab, you can click Security Options to pick how many times the drive is overwritten: once, three times, or seven times. Once is considered enough for regular purposes, while three and seven correspond to different U.S. government security guidelines.
Before Lion, you had to boot from a CD or DVD system disk or a third-party utility, like Disk Warrior, or from an external drive with OS X installed. Then you’d run Disk Utility to erase your startup drive. But this has become easier since OS X Recovery was added in Lion. Restart a Mac and hold down Command-R after the startup chime sounds, and the computer boots into the recovery mode. Select Disk Utility from the startup menu, and you can erase your startup drive securely.
There’s a slightly different way to accomplish the same goal. First, erase a drive without the overwriting part, and reinstall OS X. After you boot, launch Disk Utility, select the startup volume, and click the Erase tab. Now use the Erase Free Space option, which also offers 1, 3, and 7 passes of erase, and only empties out unused parts of the disk. The advantage is that your computer remains available (though often slow) while this operation is underway.
Along with both Secure Erase and the Erase Free Space options, which can take a very, very long time even for a single pass, you’ve got two other options, one of which you don’t need to enable.
Even better with SSD and FileVault 2
If your Mac has an Apple-installed or third-party SSD, you can’t use Secure Erase, nor do you necessarily need it, as Apple explains in a support document (see the note at the end). SSD data can’t be trivially recovered because of how SSDs optimize storage to reduce wear and tear.
This is by no means foolproof, and one should assume that there are forensic tools available that can reconstruct erased SSDs—some are for sale, but I haven’t tested their claims. Apple doesn’t provide in-depth details on why it made its statement about SSDs as it does for some security claims, and thus it’s impossible to confirm.
However, there’s a simple way with both SSD and regular hard drives to perform a fantastically quick and reliable erasure: using FileVault 2. FileVault 2, the full-disk encryption (FDE) option that first appeared in OS X 10.7, keeps your startup drive encrypted at all times. Whenever you boot your Mac and log in to one of the accounts that’s authorized to boot with FileVault 2, OS X encrypts everything written to disk and decrypts everything read on the fly.
With a FileVault-encrypted startup disk, you can restart into OS X Recovery and launch Disk Utility to erase the volume. However, before erasing, you need to select the disk and then choose File > Unlock “volume name”. Enter the password for any FileVault-enabled user account, and the disk is unlocked and can be erased.
Erasing a FileVault-encrypted volume discards the key that’s associated with it, turning a disk into a nearly perfect cacophony of irrecoverable randomness. Without the key, which is uncrackable in any realistic period of time by any current technology, the erased data is as good as gone as if it had been written over millions of times.
You can then install OS X on that partition, either from the recovery system or via an external drive.
A few other recovery and FileVault issues
Reader Peter wondered how FileVault figures in to cloning a disk. Because FileVault encrypts an entire drive and only decrypts files when you’re logged in, it has no effect on how or whether you make a clone, use Migration Assistant, or copy files.
However, if you’re planning on using FileVault on the new computer, I would heavily suggest enabling FileVault on the new machine before moving any files to it. This will speed up the operation by encrypting the new computer’s fewer files first. When FileVault has finished and your new Mac has rebooted and you’ve logged in, then start the migration process, and all new files are encrypted on the fly.
Andrew Robertson writes that when he upgraded to Yosemite, his recovery drive remained out of date with 10.9 Mavericks. Then, when trying to set up FileVault and enable iCloud-based recovery of his key, he doesn’t see an option to do so when booting into OS X Recovery.
Fortunately, there are answers for both:
You can reinstall 10.10 on the startup disk without damaging the rest of your setup, though make a backup first. This should upgrade the recovery partition. (Carbon Copy Cloner can clone a recovery partition from one drive to another, but it can’t create one from an installer or from scratch.)
The reset password option isn’t available with FileVault 2, but you can store a copy of your recovery key with Apple. To recover a key, first start up OS X normally, and enter the wrong password three times. (This is also how to use iCloud password recovery on non-FileVault systems.) You’re then presented with the option to contact Apple, which requires speaking to a representative, and answering multiple questions exactly as you entered them when setting up the recovery option. If correct, Apple’s customer service gains access to the stored key, which they provide to you.
Ask Mac 911
We’re always looking for problems to solve! Email us at [email protected], tweet them at me (if brief) @glennf, or call 206-337-5833 and leave a voicemail message. (We’ll be experimenting with some audio in the future, and may put your question “on the air.”)
Mac 911 can’t provide direct email responses or answers for every question. For that, turn to AppleCare, an Apple Store Genius Bar, or the Apple Support Communities.
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Uninstalling an app on a Mac is so easy, you might not even realize how to do it: just drag the app’s icon from the Applications folder into the trash. But what about applications that don’t have shortcuts, built-in system apps, and other corner cases?
This will cover most situations, but not all of them. This method leaves some junk behind, for example, but it’s mostly okay to leave it there. Some other apps may have different uninstall processes, too. So let’s look at all the different things you need to know when it comes to uninstalling applications.
How to Uninstall Most Mac Applications
RELATED:How to Install Applications On a Mac: Everything You Need to Know
Most Mac applications are self-contained items that don’t mess with the rest of your system. Uninstalling an application is as simple as opening a Finder window, clicking “Applications” in the sidebar, Control-clicking or right-clicking the application’s icon, and selecting “Move to Trash.”
You can also drag-and-drop an application’s icon to the trash can icon on your dock. Or, open the Launchpad interface and drag-and-drop an application’s icon to the trash can from there.
Most applications will go straight to your trash, and you can then Control-click or right-click the trash can icon on your dock and select “Empty Trash” to get rid of that application and all the other files you’ve deleted.
However, some applications will prompt you for a password when you try to move them to the trash. These applications were installed using the Mac package installer. Uninstalling them will remove whatever system-wide changes they made.
Note that you can’t remove built-in applications by doing this. For example, try to move the Chess app to the trash and you’ll see a message saying, “Chess can’t be modified or deleted because it’s required by OS X.”
How to Remove Left Behind Files
The above method doesn’t actually erase an application’s preferences. Erase an application and it will leave preference files left over in your Library folders. Most of the time, these files will use very little space and won’t cause a problem. The preferences will still be available on your Mac, too — this is convenient if you’re uninstalling an app only to replace it with a newer version of the same app, or if you reinstall the app later down the line. It’ll keep all your preferences from when you had it installed before.
RELATED:How to Reset Any Mac App to Its Default Settings
If you absolutely must remove those files (say, if you want to reset an app to its default settings), you can use a handy app called AppCleaner to fully uninstall an app, along with all its extra files. Just launch AppCleaner, search for an application in its main window, and click on it, then click the “Remove” button in the popup window that appears.
How to Uninstall Apps That Don’t Appear in Your Applications Folder
But what about applications that don’t appear here? For example, install the Flash plug-in for Mac OS X, or the Java runtime and browser plug-in for Mac, and neither will appear in your Applications folder.
On Windows, that’s no problem — the Control Panel shows a list of all your installed programs, even ones without shortcuts. On a Mac, there’s no interface that lists all your installed software so it’s tough to even notice if you have this stuff installed.
Some applications must be removed in other ways, and you’ll generally find instructions by simply performing a web search for “uninstall [program name] mac”. For example, Adobe offers a separate uninstaller app you need to download and run to uninstall Flash on a Mac.
RELATED:How to Uninstall Java on Mac OS X
Oracle is even worse and doesn’t provide an easy app that will uninstall Java from Mac OS X for you. Instead, Oracle instructs you to run several terminal commands to uninstall Java after installing it. Here’s how to uninstall the Java runtime and development kit.
Come on, Oracle — at least provide a downloadable uninstaller like Adobe does.
Other software applications may provide their own downloadable uninstallers or uninstallation instructions, so perform a web search if you’re not sure how to uninstall something and you’ll find instructions.
How to Uninstall Adware and Other Crapware
RELATED:How to Remove Malware and Adware From Your Mac
Macs are now falling prey to the same epidemic of crapware Windows PCs have to deal with. The same free application download websites that serve this junk up to Windows users are serving similar junk to Mac users.
On a Windows PC, most “reputable” adware provides an uninstaller that sits in the Programs and Features list, allowing users to easily uninstall it for legal reasons. On a Mac, adware programs don’t have a similar place to list themselves in. They may want you to download and run an uninstaller app to remove them, if you can even figure out which ones you have installed.
We recommend the completely free Malwarebytes for Mac if you need to purge your Mac of crapware and even Mac malware. It’ll scan your Mac for junk applications and remove them for you.
How to Remove Built-in System Apps
Macs also have no way to uninstall or install operating system features, so there’s no way to easily remove the many applications Apple included with your Mac.
On OS X 10.10 Yosemite and earlier, it was possible to open a terminal window and issue commands to delete these system apps, which are located in the /Applications folder. For example, running the following command in a terminal window would delete the built-in Chess app. Be very careful when typing the following command:
sudo rm -rf /Applications/Chess.app
As of Mac OS X 10.11 El Capitan, System Integrity Protection protects these applications and other system files from being modified. This prevents you from deleting them, and it also ensures malware can’t modify these applications and infect them.
RELATED:How to Disable System Integrity Protection on a Mac (and Why You Shouldn’t)
Everything Program For Mac Os
If you actually did want to remove any of these built-in apps from your Mac, you’d have to disable System Integrity Protection first. We don’t recommend that. However, you can re-enable SIP after and your Mac won’t mind that you’ve deleted Chess.app and other built-in system apps.
Parallel Program For Mac
Really, we recommend you don’t do this. Mac OS X may automatically reinstall these applications in the future when you update the system, anyway. They don’t take up much space, and Apple provides no way to get them back beyond reinstalling OS X on your Mac.
Image Credit: Daniel Dudek-Corrigan on Flickr
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