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Data Recovery

By Lasa Information Systems Team

There are all sorts of reasons why you may need to recover lost data. This article explores some of your options should the worst happen.

What is data recovery?

Data recovery is the retrieval of data (files etc.) held on damaged media such as computer hard disks, tape or other removable media such as floppy disks, CDs / DVDs etc. One of the most common reasons data recovery is needed is that a hard disk simply fails. This can be due to physical reasons such as mechanical or electronic failure, or "logical" reasons such as file corruption.

Other situations in which data recovery might be needed include loss or damage due to software failure, computer viruses, human error, or if you're really unlucky, theft, fire, flood or some other natural disaster. The first thing to say is it's best to avoid having to go through the process of data recovery in the first place.

It is important to have a solid data recovery plan before disaster strikes. Part of this will involve regularly backing up your data to an external source e.g. tape, CD, DVD, external hard drive etc. For more information on backing up your data see the resources section at the end of this article.

But I don't have a back up!

Assuming you didn't back up your data, or worse still, you did but there is a problem with the backup (you mean you never checked to make sure you could restore your backup safely? Tut tut!), or with the best will in the world things can sometimes go badly wrong despite taking sensible precautions; for example, even brand new hard drives sometimes fail…

If the worst happens, what are your options for getting back that valuable data?

Specialist software

You should not attempt to use specialist software yourself unless you know what you are doing! Data recovery software utilities exist for different  platforms e.g. Windows and/or Linux operating systems, PCs or Macs. An Internet search for "data recovery software" will reveal that there are literally dozens of products available that claim to be able to recover data from damaged hard drives, and removable media such as CDs, DVDs, USB drives etc. So how do you know which products are reliable or even safe to use?

  • As ever, a general rule of thumb is "you get what you pay for", though that's not to say that a low cost option won't do a decent job for you.
  • Choose software from a reputable company and check to see what sort of reviews the software gets from reputable and independent sources. Make sure there is some kind of support available for the product.
  • Make sure the software does not write anything at all to the damaged disk as you run the risk of overwriting data that may otherwise have been recoverable. Alternatively, decent utilities that can recover your computer from logical disk drive problems will usually have some kind of "undo" file that contains a record of the changes made to the file. Keeping a copy of this file is important so that you can revert back to a previous state, or you can pass a copy of the file on to a data recovery company if you find you later need to use one.
  • If your computer's hard drive is physically damaged, it may be unsafe for you to attempt to run this kind of software utility. For example if your hard disk is making unusual grinding, buzzing or scraping noises (indicating that it is physically damaged), the safest thing to do is turn the computer off immediately after backing up any critical or important files, and call an expert for help. If the hard drive is physically damaged, rebooting or keeping the hard drive running for any length of time could cause further damage and render the data unrecoverable. Similarly you may need to power off a computer immediately if its hard drive suffers water damage, is affected by a power surge, or suffers some kind of physical impact. Another possible indication of physical damage is that your computer does not detect the presence of a hard drive.
  • Finally, proceed with caution as you could increase the risk of permanent data loss! Depending on the severity of the situation, you may well be better off leaving it to the experts.

Data recovery software utilities are generally most useful when used preventatively, and to recover from relatively minor data corruption issues ("logical" disk drive problems) - i.e. they work best when installed before they are needed. In some cases data recovery utilities can be installed after a crash or physical hard disk damage.

Data recovery software typically works by performing some kind of diagnostic scan to determine the extent of the damage to the disk. Once this has been established the software will attempt to recover the data in a way that will not cause further damage.

Examples of data recovery software (rather than recommendations) include:

Norton Utilities - part of Norton System Works for preventative maintenance. (The premier edition of System Works also contains Norton Ghost which allows you create a backup of your hard drive or removable media so that you can recover data more easily if needed).

Spinrite:  SpinRite runs from a bootable CD and uses a number of methods to recover data.  It can also be run in maintenance mode, although for large hard drives this is likely to take a long time.

Ontrack Easy Data Recovery - scans the media for lost data and allows the user to copy lost files and folders to a safe location.

Specialist companies

If your computer's hard drive suffers physical damage or file corruption, you may need to engage the services of a data recovery company. A reputable company should have the necessary experience, equipment, hardware and software tools to do the job properly and maximise the chances of recovering that valuable data. Like data recovery utilities, there are dozens of companies offering data recovery services. Not all of them will be any good, so how do you sort the wheat from the chaff?

Some things to check include:

  • How long has the company been in business, and do they have any past customer testimonials you can check with?
  • Will they give you a free evaluation? A decent data recovery company should be able to do an evaluation of your disk to determine what the problem is (i.e. logical or file corruption issue, or physical damage). From the evaluation the company should be able to give you some idea of what and how much data can or cannot be recovered and how long the process is likely to take.
  • Will they give you an upfront cost? Most reputable companies should be able to give you quote plus or minus a couple of hundred pounds or so. You may get back a couple of quotes that will be different depending on whether the problem is physical or logical (the price for recovering data from a physically damaged drive will usually be higher).
  • Especially if the data is highly confidential, what sort of procedures do they have in place to keep your data safe?
  • Do you feel comfortable that the company is one you're happy to entrust your data to after talking to them?

It's worth talking to at least a couple of companies before committing (but of course, the speed at which you need to get your data back will determine how much time you have to do this). Once you've narrowed down your possibilities make sure you get a written quote for the work first. You don't want any nasty surprises down the road (it's already probably going to cost you loads of money).

Examples of UK based data recovery companies include:


Whether you're using software utilities or a data recovery company, getting your valuable data back can take several hours, days or even weeks! It could also turn out to be very expensive and although the average success rate for data recovery professionals is around 75 - 85%, there is no guarantee at the end that the process will be successful!

So, make sure you back up your important data - if it's really important have more than one back up and check the backups can be restored successfully.


About the author

Lasa Information Systems Team
Lasa's Information Systems Team provides a range of services to third sector organisations including ICT Health Checks and consulting on the best application of technology in your organisation. Lasa IST maintains the knowledgebase. Follow us on Twitter @LasaICT


Backup, bootable, Disk Drive, DVD, Floppy Disks, Hard Disk, Hard Drive, Hard Drives, Hardware, Internet, Linux, Software, USB, WWW

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Published: 9th February 2021 Reviewed: 23rd April 2021

Copyright © 2021 Lasa Information Systems Team

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