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Computers

An Introductory Guide to Data Recovery

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This post is part of a series called Data Backups and Storage.
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Data loss is something that no one ever wants to go through, but unfortunately, a lot of us will at some point. Whether it's a lost thumb drive that we failed to back up or an accidental deletion of an important folder, potential hazards are everywhere. Prevention is your first step, but in the case that you do encounter a disaster, this guide will help you through it.


Have a Backup Plan

Data loss is almost completely preventable and having a good backup plan is crucial. Data recovery is never an alternative to backing up. Data recovery is far less reliable in its results and can costs anywhere from $100 to $5,000. That said, almost all data is recoverable in some shape or form - the only obstacles are time and money. The more time and money you are able to provide, the better the odds.

Backing up your Mac to an external hard drive using Time Machine will protect your data
Backing up your Mac to an external hard drive using Time Machine will protect your data

With OS X including Time Machine functionality for a number of years, there’s absolutely no reason any Mac user shouldn’t be backing up. Time Machine not only protects against a complete system crash, but backs up often enough that you can even recover from small mishaps such as overwriting a single file.

Tip: In addition to this tutorial, I advise you to take a look at two other articles: “Create a Foolproof Backup System for Your Mac” and “How to Create an Awesome Diagnostic Drive for Your Mac”. These will come in handy!


What Can Happen?

In most cases I’ve seen where someone has lost data, it’s because there was no backup strategy at all. In my days on the Genius Bar, of the cases where the hard drive failed, very few had a working backup. In other words, most of the people who experienced a hard drive failure had to contend with the notion that all their data was gone.

Data loss is the digital equivalent of a house fire. Just like you’d protect your house and belongings from danger, you also take precautions such as home insurance for the unlikely event that something bad happens.

Having a fully working backup would mean seeing issues like this would be far less stressful than worrying about whether the data on the Mac is still intact
Back up before you ever see something like this!

As the world moves ever more digital, the average home owner is more likely to have their photo albums or music library on their computer than in an actual photo album or CDs in the attic. Think of a backup plan as an insurance policy for your personal data.


Why Does it Happen?

There are a number of reasons why data loss can occur and some of them are beyond a user’s control. Let's run through some of the most common scenarios.

Hard Drive Failure

Type: Hardware

Hard drives are not invincible. Mechanical hard drives that you find in most desktops and laptops are made up of hundreds of tiny parts and metal discs spinning at incredibly high speeds. They are the single most fragile piece of hardware in your Mac. Sometimes a fault can occur, seemingly out of nowhere. Other times you might drop your computer, leading to a damaged disk. Either way, hard drives can and do go wrong.

Macs with SSDs are not as susceptible to drops or knocks damaging the drive. However, SSDs have a finite life span. What’s worse, due to the nature of SSDs, data recovery of deleted files is far less successful.

Identifying This Problem

You’ll find that if your Mac’s hard drive has failed, it’s unlikely to boot. You may see a grey screen with a flashing folder labelled with a question mark. Your Mac may attempt to boot and display the grey Apple logo but no further.

Overwriting Data

Type: Software

Saving a file over another one by accident is an extremely common occurrence. All it takes is selecting the wrong file to save. Or worse, saving changes to a photo but before you realize those changes were a bad idea - the app quits unexpectedly, leaving you without the ability to undo.

Identifying This Problem

Usually this is an instant identification. You’ll notice that you may have saved the file over another one almost immediately. If not, you will the next time you try and open what was the original document.

Losing a USB Thumb Drive

Type: Hardware

Thumb drives are indispensable, yet they can be taken for granted. If you’ve got a thumb drive, take a look what’s on it. Anything important? Now ask yourself if you have a backup of these files.

Tip: If you’re ever using a thumb drive on a publicly accessible computer, never leave confidential, personal or financial data on it. When using a thumb drive, always assume you’ll accidentally leave it plugged in somewhere.

Identifying This Problem

As thumb drives get smaller and smaller, they get easier and easier to lose. Checking your pockets yields no results. You check your Macs, nothing. Did I leave it attached to that computer?

Accidental Deletion Of Files

Type: Software

This is likely the most common type of data loss. You’re browsing through folders to clear out some old files you might not need any more, then you hit Empty Trash and at that precise moment you think, “Wait, no!”. We’ve all done it at one time or another.

Identifying This Problem

Similar to overwriting a file, you’ll notice almost immediately. If not, you’ll notice when you try and open one of the files only to see it’s gone.


Recovering Lost Data

Data recovery can be broken up into two categories: software and hardware. As detailed above, software data loss tends to be deletion of files, overwriting data. Hardware data loss is due to a physical problem such as a hard drive fault or losing a thumb drive.

Deleted Data

When a file is deleted, it isn’t actually gone. Instead, the area of the drive the file sits on is marked as being "free to use" if and when the time comes. At any point, the data could be overwritten.

Most mechanical drives store data in a specific way so they don't tend to go back and use that free space immediately. This would be inefficient if a file was made up of bits of data scattered throughout the drive. Instead, hard drives try to keep all the bits of a file as close to each other as possible. It increases response times and reduces wear.

Because the file isn’t really gone immediately, data recovery’s chances are higher the quicker you respond to it. If you realize that you deleted a file last year, then it’s not likely to be there. If it was an hour ago, you’ve got a decent chance of getting it back.

You can perform some software data recovery without the need for a specialist firm. There are a number of software packages available for the Mac to attempt to recover data.

Tip: Depending on the recovery options, it isn’t always possible to recover the file with the exact same filename and folder it was in, like Time Machine can. Because the data was deleted, some of this information is lost. Instead, you may need to recover a large amount of data first, then filter through it.

There are two popular data recovery apps that are very highly recommended, Disk Drill and Data Rescue 3
There are two popular data recovery apps that are very highly recommended: Disk Drill and Data Rescue 3

Disk Drill: $89+

Disk Drill is a popular Mac data recovery tool. They have a free version that provides scanning functionality only. Before dropping almost $100 on recovery tools, being able to check to see if the files are recoverable before purchasing is definitely worth it!

Disk Drill can scan your entire drive to find files of a certain type, allowing you to recover them
Disk Drill can scan your entire drive to find files of a certain type, allowing you to recover them

Disk Drill can scan free space for deleted information and has some quick scan and recover tools. In addition, it includes some monitoring tools that can warn you of any potential data hazards that could occur (such as a hard drive failure).

Disk Drill can sometimes find the original file and folder you are looking for, making it easier to recover them
Disk Drill can sometimes find the original file and folder you are looking for, making recovery easy.

Data Rescue 3: $99

Data Rescue is one of the most established pieces of recovery software on the market. Brought to you by the same company responsible for Drive Genius, it has even been sold directly in Apple Stores. Its price and features are comparable to Disk Drill.

Learn more about Data Rescue.

Data Rescue includes a wizard to make recovering the data as easy as possible. If you had to stop a scan that was in progress, you can even resume it.
Data Rescue includes a wizard to make recovering the data as easy as possible.

Data Rescue 3 is also available for Mac and PC (both at the same price point).

Deep scanning
Deep scanning can take a very long time to do, depending on the size of the drive.

Once completed, Data Rescue will provide you with a list of all recoverable files. Again, filenames and locations aren’t always available.

Data Rescue will do it’s best to get as much information from the file as possible.
Data Rescue will do it’s best to get as much information from the file as possible.

Tip: When recovering data, these apps will advise you to have an external drive handy. The reason is that you cannot recover data from a hard drive onto itself. It has no control over what part of the drive the data can be recovered to, which means it could potentially overwrite itself!

Common to both Disk Drill and Data Rescue is their scanning methods. Both apps have a quick scan and deep scan feature which has to be run first. Quick scan will usually just scan the free space on a drive for deleted files. Deep scan will scan the entire drive. Deep scan can take literally days to complete so it’s always worth running the quick scan first.

Overwritten Data

This is very tricky and depending on how the application you used saved the file, using tools for deleted data may or may not work. Overwriting a file isn’t the same as deleting it and creating a new one. Deleting a file just marks the data as available to be used but doesn’t modify it. Overwriting the data actually changes it. Because of this, it’s still recommended to try the above software tools first, but unlikely to be of use.

Lost Thumb Drive

This isn’t something any piece of software will be able to assist you with unfortunately.

Instead, try to retrace your steps. Check your pockets on all your clothes, bags, rucksacks, anywhere it might have gotten. In addition, check your washing machine - you’d be surprised how often they can end up there!

What To Do When A Hard Drive Fails

We saved the worst for last. A hard drive failure can be catastrophic. A physical fault will mean no amount of data recovery software you use will help.

Tip: Before continuing, if your suspect your Mac of a hard drive failure and it does still work to some extent, back up as much data as you possibly can before taking it to an Apple Store.

Let’s assume one day you turn on your Mac, only to be greeted by the grey screen with a flashing question mark folder. This is bad, as it means it can’t find an operating system to use. At this point, heading to an Apple Store or Apple Authorized Repair Center as quickly as possible will minimize the downtime and get you up and running sooner rather than later. If the hard drive is faulty, then software tools aren’t enough. From here, you need to look to data recovery companies.

Data Recovery Companies

Data recovery companies are actually quite common. Governments, law enforcement agencies and corporations make use of them every day. These guys can recover data from fire-damaged, water-soaked hard drives that have been blown through a window. There’s a reason why governments will literally shred hard drives. Smashing and blowing them up isn’t enough!

It’s impossible to quote pricing for the data recovery companies listed here, so I’ve provided links to their contact information instead.

In addition to being able to run much more powerful software, these data recovery companies will make repairs to a drive for the sole purpose of recovering the data. The repairs made won’t bring the drive back to a working order, but they will provide enough of a fix to extract the data. The more damaged or faulty the drive, the more of a repair will be needed and the higher the associated costs will be.

Tip: To keep costs down, be as specific about data as you can. Don’t just ask them to recover everything, the applications and system folders are not worth recovering. Instead, if you only need the photos, let them know. The less time they need to recover the date, the cheaper it is for you!

The repairs made won’t bring the drive back to a working order, but they will provide enough of a fix to extract the data.

Data recovery companies can temporarily resurrect failed hard drives enough to recover data.

Data recovery companies can temporarily resurrect failed hard drives enough to recover data.

Ontrack

Ontrack is one of two data recovery companies that Apple officially recommends, they provide consumer and professional data recovery from almost any type of storage.

DriveSavers

DriveSavers is the second of two officially recommended companies by Apple. DriveSavers also offers a cool iPhone app that simulates the type of faults a traditional hard drive can suffer, as well as contact information.

As Apple has worked with these companies in the past, it’s highly recommended you work with them as well. If you’ve been referred to them from an Apple Store, they may even offer a discount (Ontrack has historically offered a fixed 10% discount). The companies are also worldwide, so you should find a recovery center you can contact. Don’t worry about living near them, they’ll arrange to collect any drives you may have.

These two companies are some of the best in the business. However, you may not be able to easily reach them. If you need to find one closer to you, then make sure they are reputable. Check out reviews and see if they have more than one office or .location

If you’re looking to take an entire Mac to them (such as an iMac) because removing the drive is extremely complex, then either make sure the company has an Apple authorized engineer available or take it to an Apple Store or Apple Repair Center first. While they might be able to recover the data, if they break the Mac, they may not be able to fix it.

Tip: Be warned, data recovery is not a quick process and it’s definitely not cheap!


The Age of SSD

SSDs are finding themselves in a lot of the Mac’s product line. Their prices are continuously dropping and the performance compared to mechanical drives is much better. However, the way they store data is fundamentally different. Unlike mechanical drives where data isn’t immediately overwritten, SSDs do the exact opposite. They don’t suffer from the same type of fragmentation as mechanical drives and data recovery on an SSD is still in its infancy.


Time Machine

Time Machine has been around in OS X for quite a few years now and has become extremely versatile. Not only does it back up your Mac in case of a system failure, but it backs up all changed files every hour that it’s running. That means if you delete, edit or overwrite a file and realize a few weeks later that you screwed up, Time Machine will be able to bring it back.

If your hard drive fails or is wiped, you can reinstall your Time Machine backup during the OS X installation or with Migration Assistant. In fact, Time Machine is a good way of setting up a new Mac as you can just plug the drive in, tell the new Mac to use the Time Machine backup to migrate your information from and voila!

What If You Only Have Your Time Machine Drive?

In the event that your Mac is in for repair and you desperately need that file from your Time Machine backup, you can easily access it using another Mac.

Connect your Time Machine drive to another Mac and hold down the Option key while clicking on the Time Machine icon in the menu bar. From here, you’ll see a menu option to Browse Other Backup Disks. You will then be able to browse the Time Machine drive just as if you were on your own Mac!

Using another Mac is just another way Time Machine can prevent data loss from becoming a problem!
Using another Mac is just another way Time Machine can prevent data loss from becoming a problem!

Wrapping Up

As the old saying goes, “the best offense is a good defense”. With that, having a good backup plan such as Time Machine is the best way to prevent problems with losing data in situations such as a hard drive failure. Remember, a backup plan is an insurance policy for your data. Imagine if your data disappeared one day. If that would be a cause for alarm, then you need a backup.

Have you ever experienced data loss? If so, what was it like and did you have a backup solution in place or did you have to contact a data recovery center?

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