Publishers of technology books, eBooks, and videos for creative people

Home > Articles > Apple > Operating Systems

The Top Mac Hard Drive Utilities, 2010 Edition

  • Print
  • + Share This
Ryan Faas, updating his highly popular article from 2007, evaluates some of the best tools for analyzing and repairing problems with Mac hard drives and directory structures.
Like this article? We recommend

Computers can develop many problems, including hardware damage and defects, operating system and application issues, and malware. While Macs tend to have lower incidences of some of these problems (malware in particular), they aren't immune to having issues that require some diagnostic and repair work.

Some of the most common problems that Mac users experience have to do with hard drives. Hard drive problems come in two general types: physical damage to the drive itself, and directory or file system damage. Physical damage is less common but more severe, because the drive—or, in rare cases, the circuitry that connects the drive to the motherboard of the computer, known as the drive controller—no longer functions. Repairs for physical damage typically require replacing the drive, often without being able to recover the files stored on that drive. (I'll talk about data-recovery tools and options in a future article.)

More common—and much easier to fix—is damage to the directory structures and the file system on a hard drive (or a removable drive, such as a flash drive or camera memory card). The directory structures of a drive are created when the drive (or partition) is formatted; they act as a map to the sectors or blocks on a disk where the data is stored. These structures are important because they enable the Mac to locate the pieces of data that make up a file. If a directory is damaged or corrupted, you may not be able to locate or open files, applications may behave erratically, or the Mac may not start from the affected drive.

In cases severe enough to render the Mac unable to boot from a drive, typically you can use an alternate startup disk, such as another hard drive or partition, a Mac OS X install or restore DVD, a hard drive utility DVD, or a disk inserted in another Mac (such as is required for the MacBook Air or Mac mini server, which ship without a built-in DVD drive). In these cases, you may be able to see and access the affected drive, or the drive may have suffered damage or corruption bad enough that the Mac will be unable to mount the drive at all. Even if the drive is accessible, you may want to use a utility to determine the type and extent of the damage (and rule out physical damage) before attempting to open or copy files. In these situations, you may not be able to open or copy files that are affected by the directory corruption.

In addition to problems with directory or file systems on a drive, the file permissions on individual files or folders may become corrupted or may be set improperly. This situation can lead to issues ranging from not being able to open a file or application, to erratic behavior of affected applications, or even to erratic behavior and lack of access to system components of Mac OS X (such as Apple-provided utilities, or configuration options such as those in System Preferences). Improper permissions can also have the opposite effect, giving users or applications greater access to core system files and settings than they should normally have.

Permissions on system and application files are specified by package (.pkg or .mpkg) files that are read by the Mac OS X Installer utility. All the Mac OS X system files, as well as files by most third-party applications, are bundled as package files. Some applications don't use packages because you only need to copy a single application file to your hard drive to install the app, or because the application is installed by a third-party installer (though such installers are much less common today than in the past).

After the Mac OS X Installer utility places application files in the appropriate locations with the appropriate permissions, it writes a copy of the package to a special Receipts folder, which is located either in the Library folder at the root level of a startup drive, or in the Library folder of your home folder. This design allows various tools to verify or repair (if needed) the permissions of both system and application files.

For the four utilities covered in this article, I'll describe how various tools can be used to solve these types of problems. I'll also cover additional features that the tools provide for preventing and resolving problems, as well as for working with advanced hard drive and data features.

Disk Utility

Disk Utility is a powerful tool that's part of every Mac OS X installation and available from the Mac OS X Install and Restore DVDs. Although it's a free tool provided by Apple, Disk Utility can diagnose and resolve a range of hard drive issues, and it offers a set of features beyond basic disk setup and repair.

For diagnostic purposes, Disk Utility offers the ability to verify the directory structures and file systems of a hard drive or partition (called First Aid). It also can verify the permissions on all of the Mac OS X system files, as well as any applications installed via package files. If problems are detected with either the directory structures or permissions, Disk Utility can attempt to repair them.

In repairing directory structures and file systems, Disk Utility looks at the actual content on a drive or partition and adjusts errant directory entries to match the condition of the drive. Disk Utility is often successful in such repairs, but the routines that it uses may not always be able to restore the drive. In these cases, you can try other utilities. In the case of permissions, Disk Utility is almost always able to repair permissions, as long as the files written to the Receipts folders aren't moved or deleted.

Disk Utility can also query hard drives for their S.M.A.R.T. status , which can indicate hardware problems or physical damage. Such problems cannot be repaired by a hard drive tool; they generally require replacing the drive—or at least backing up data if the drive is still readable.

In addition to diagnosing and repairing problems, Disk Utility can partition or repartition hard drives into multiple volumes, typically without needing to erase the drive in the process, which was required in older versions of Mac OS X. You also can use Disk Utility to clone the contents of one hard drive to another (called a restore) and create disk image files.

Disk image files are displayed with a .dmg extension. When opened, they mount on the desktop like a hard drive or removable disk. They can be used as a way of packaging a number of files for easy storage, or for transfer by email or other means. You can also clone an entire hard drive as a disk image to use later for a restore option or as a backup; this is a common approach for businesses and schools that must deploy a number of identical Mac systems.

When creating disk images, you can tell Disk Utility to compress the data to save space while copying it to the image. You can also opt to create encrypted disk images that can only be opened with a password that you enter when creating the image. This makes the images useful as a secure storage solution for sensitive or confidential files.

You can also use Disk Utility to mount or eject disks. If a disk doesn't mount automatically, or if a non-removable drive has been "ejected" (unmounted), and therefore it's not accessible to the Mac, you can use Disk Utility's Mount command. For some disks that have sustained either physical damage or directory damage, this capability may provide access to files and folders. Finally, Disk Utility offers the ability to erase a hard drive, partition, or external/removable disk (including flash drives, camera memory cards, and rewritable CDs/DVDs).

When erasing a drive or partition, you can use a simple erase, in which sectors on the disk are marked as free and used to store new data as needed, or you can choose from a variety of secure erase options that write over those empty sectors with blank replacement data. You can erase in one pass, seven passes (the U.S. Department of Defense's definition for a secure erase), or 35 passes. The more secure the erase option you choose, the longer the erasing process takes, because the entire drive must be overwritten that many times.

In addition to erasing an entire drive, you can simply erase the free space of a drive. This option securely erases any sectors on the drive that are marked in the drive's directory as not containing active data. It securely erases any previously deleted files (but not files that are currently in the Trash). The Secure Empty Trash feature in the Finder also performs this function, but using only a single-pass erase, and it affects only files that are currently in the Trash. Using Disk Utility, you can perform more secure erasures of previously deleted files.

With this powerful set of tools, Disk Utility may be the only hard drive utility that most users will ever need.

The three tools I'll cover in the remaining sections of this article are commercial hard drive utilities. They all offer the same basic features as Disk Utility, but each tool has its own set of additional features and capabilities that make the tool worthy of investment.

  • + Share This
  • 🔖 Save To Your Account

Peachpit Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Peachpit and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Peachpit products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive:

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020