How To: Recover deleted files

If you have deleted files from your hard drive, don't panic! Using the right unerase software deleted files can be recovered very easily. Success is more or less guaranteed as long as you act as soon as you realize that the files are missing.

Even if your files have been overwritten or corrupted, if the disk they were stored on has been formatted or repartitioned, or if you don't know how they were lost, it's still likely that you can recover them. To find out more about data recovery read How To: Data Recovery. If you have lost files from CD or DVD, see How To: CD Data Recovery. But if you only want to know how to recover deleted files, just read on!

Recommended undelete software

For Windows users:

• Use Uneraser.

For Apple Mac users:

• Use Data Rescue II.

When a file is deleted from your computer, it is not really deleted. It is simply removed from the directory of files in the folder.

If you're using Windows and you deleted the file using Windows Explorer, the file will not have been erased from the disk. It will have been moved to the Recycle Bin. If you're a Mac user, it's moved to the Trash. If you use Linux KDE, it's the Wastebin. Whatever the bucket shaped object is called, as long as a file remains there it can easily be restored in its entirety, with no problem at all. So the first thing to do when you want to recover a deleted file is look in the Recycle Bin / Trash / Wastebin.

If the file you need isn't there - if you emptied the bin, used Shift Delete to get rid of the file, deleted it from within an application or used some other method of removing it that bypassed the bin - then don't despair. It's almost certainly recoverable. When you empty the Recycle Bin or delete a file using another method, the file is still not really deleted. The file no longer exists as far as the operating system is concerned, and the space it occupied becomes available for re-use by other files. But the disk space does not get re-used straight away, so the data contained in the deleted file will stay on your hard drive for some time to come.

A frequent misconception is that the System Restore feature of Windows Millennium, Windows XP and Windows Vista can be used to recover deleted files. However, it is no help at all. System Restore was developed specifically to restore system files back to an earlier state. Its purpose is to enable easy recovery when a software update, installation or removal has an adverse effect on the system. It provides a simple way to roll things back to a point in time when everything worked.

Think about it. It would be very annoying if, when you used System Restore to get your computer back to the state it was in a few days ago, it removed all the letters, emails and other documents you'd received or created since then as well. So System Restore ignores file types associated with office documents, photo images, music files and other things that are of interest to you. It doesn't back them up in a Restore Point, so it can't restore them.

Chances of recovery

Because the operating system doesn't immediately re-use space from deleted files, a file can be recovered or undeleted right after it has gone, and for a fair while afterwards. But the chances of a perfect undelete decrease the longer you leave it, because eventually some or all of that space will be re-used.

The chances of recovery also depend on how full your computer's hard drive is. Windows tries to avoid re-using disk space that has recently been freed, to give deleted file recovery software a better chance of working. But the fuller a drive is is, the sooner the freed-up space is going to be used by other files.

If you have defragmented the hard drive since the file was deleted, then this has severely harmed the chances of a successful recovery. Current files will have been moved into the free space left by deleted files in order to reduce fragmentation, making it much less likely that undelete software will be able to find anything useful.

Recover deleted files

Tools that can help you undelete files are not provided as standard in any operating system. So you will need to use undelete software.

Undelete software understands the internals of the system used to store files on a disk (the file system), and uses this knowledge to locate the disk space that was occupied by a deleted file. As we've already said, because another file may have used some or all of this disk space, there is no guarantee that a deleted file can be recovered. But usually it is successful. In fact, Uneraser users have often been amazed to find that it recovers files that were deleted months or even years ago. The best undelete programs give you an indication of the chances of recovering a file intact, and even provide file viewers so you can check the contents before recovery.

If you're running Microsoft Windows we consider that DiskInternals Uneraser is one of the best undelete software products available. Uneraser has powerful tools to help locate lost data among the thousands of files on a hard drive. It also has the widest range of built-in viewers to let you examine the files it finds before recovery. There is a free trial version so you can see for yourself whether it can recover the files you lost. If a file looks perfect in the viewer then recovery is pretty well 100% guaranteed. See a tutorial showing how to recover deleted files using Uneraser.

For Apple Mac users we recommend Data Rescue II. The standard version is installed on your Mac, but if you need to you can obtain an .dmg file to create a boot CD that allows you to run the software from that. Again, there's a free demo, so you can see if it will get your files back before paying for it.

Recovering files from your main drive

One of the cardinal rules of data recovery is that you must stop using the disk that contains the files you want to recover as soon as you realize they are lost. This is because anything that gets written to the drive could potentially be written to the space that was holding the data you hope to recover. If the files you lost are on your computer's main or only drive (normally the C: drive in Windows) then using the computer at all is inadvisable, because even if you avoid writing to that drive, Windows will still be doing so.

You can avoid this potential problem by running data recovery software from a boot CD. The DiskInternals data recovery boot CD builds a Windows based recovery CD using the Windows installation files found on most PCs (for the benefit of technical types, it uses BartPE.) This allows you to run Uneraser and other DiskInternals data recovery tools under a familiar Windows interface. Alternatively, you can use Data Rescue PC, which comes ready to burn to CD (you can also order a ready to use CD through the post at extra cost.)

If it seems like too much work to create a bootable data recovery CD then of course you can always take a chance on installing software such as Uneraser on your main hard drive. If you have a large drive and most of it is unused then there may be only a small possibility that the software installation will overwrite your data. It's your data, so the decision is up to you, but don't say we didn't warn you!

Saving the recovered data

Because it is bad practise to write to the drive that contains the deleted data, you should save the files that have been recovered to a different drive to the one they were recovered from. This could be an external drive or a network share, even a USB memory stick. The Uneraser product recommended here has the ability to burn files direct to writeable CD or DVD without creating any temporary files on the hard drive. It even allows you to save the files to an FTP server.