This article will show how to recover files from an external hard disk with a damaged file system, but the same technique can be used for file recovery from accidentally deleted or formatted disks, or retrieving files from disks with file systems that Windows doesn’t support, for example Apple's HFS+. The procedure is generally the same for all those cases with slight differences which we'll show in the corresponding points.

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R-Undelete: File recovery from a non-functional computer

The most probable cause for file system damage on an external disk is its improper removal from a computer. All operating systems have a special "eject" command which prepares the disk to be disconnected from a computer. This ensures that the computer is not writing anything on the disk when it is disconnected. If the operating system is accessing the disk when it is removed, the disk's file system may be damaged, and the files on the disk may become inaccessible. The computer will be unable to recognize the file system or may see it as an empty disk. Windows Disk Manager shows such disk as unallocated space or as a partition with an unsupported file system (no disk letter is assigned), and Windows may ask you to format it when attempting to access it.

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Fig.1. Disk with a damaged, deleted, or unsupported file system in Windows Disk Manager

Although it looks like the files on such a disk have been completely wiped out or lost, in most cases, they haven't been. Some or all your files may still be on the disk, even if the operating system doesn't see them. R-Undelete is a file recovery program that helps you to "see" those files, find, and recover them. Below we will show how to do that in several easy steps.

Before we begin file recovery:
First and foremost: Don't panic! In most cases you will be able to get your files back. You don't have to be a computer expert for successful file recovery. Still, we recommend you read our article "File Recover Basics" to better understand how file recovery works and what it can and cannot do.

1. Check that the disk has no hardware problems. And if it has, stop any further file recovery attempts by yourself and seek out a help from a professional data recovery specialist. Beyond checking that the cables are firmly connected, any "do it yourself" file recovery efforts may actually worsen your chances of recovering the data if your disk has a serious physical malfunction. Signs that a disk has a physical failure include:

• The system does not recognize the device at all, or it appears with an unusual or garbled name.
• A S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) utility (R-Undelete, for example) warns that a severe hardware failure event has occurred.
• The hard drive makes unusual noises, clicks, or takes a very long time to spin up and initialize.
• Bad blocks continually appear on the drive.

All these cases are best handled by qualified data recovery professionals only. They have special equipment, software, and, most important, the required skills to work with such drives. Neither R-Undelete, nor other data recovery software will help you in such cases. Moreover, any further tampering with such a drive will surely inflict more damage to your files. Quite often, such damage will render the files completely irrecoverable

2. Find enough room to store recovered files. They will be copied from the original disk to that place. R-Undelete can save files on any local or network disk visible by your computer.

Download and install R-Undelete. You don't have to buy it immediately. File recovery from FAT/exFAT disks is free, however for the NTFS, you may start in Demo mode and check whether R-Undelete can recover your files or not. If R-Undelete predicts the file recovery will be successful, you may buy and register on-the-fly without interrupting the file recovery process.

4. Connect the external disk to your computer. It's better to use the fastest eSATA (external SATA) connection, but a USB3.0 will also do. USB2.0 is much slower and more time may require for the file recovery process.

Now we can start actual file recovery:

1. Locate the disk with the damaged file system
Most likely, R-Undelete will show it as a disk with an unrecognized or unallocated space. A deleted disk will be shown as an unallocated space.

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Fig.2. Disk with a damaged file system in R-Undelete

Sometimes, a partially damaged disk may appear as a disk (partition) without an assigned disk letter. A formatted disk looks the same way, only it has the disk letter.

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Fig.3. Partially damaged and formatted disks in R-Undelete

We'll show how to recover files in such cases a little bit later in the File recovery from formatted disks or disks with partially damaged file systems section. If this is your case, you may jump to this section right after you've read about disk S.M.A.R.T. check.

For all cases, we advise you to check its S.M.A.R.T. attributes first to be sure that the disk is in a healthy state. To do so, right-click the icon of the hard drive and select Show S.M.A.R.T. on the shortcut menu.

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Fig.4. S.M.A.R.T. attributes for the disk with a damaged file system
As the hardware state of our disk is good, we can proceed further with file recovery.

2. Scan the disk
Move the mouse over the Unrecognized / Unallocated space icon and select Scan.

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Fig.5. Disk scan start

R-Undelete will start scanning the unrecognized / unallocated space showing its progress.

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Fig.6. Disk scan progress

Depending on your hardware, scan time may vary, even within the same scan process, and may be quite lengthy for large disks. The scan may be paused then resumed it by clicking the Resume scan button.

When R-Undelete finishes the scan, it will show the results.

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Fig.7. Discovered partition
Depending on how the original file system was damaged, the resulted icon and text may be slight different, but the following procedure still will be the same.

3. Find lost files and mark them for recovery
Move the cursor over the found partition and select Show files on the shortcut menu.

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Fig.8. Disk scan result

R-Undelete will start searching for files on the disk. This may take a while, depending on how large your hard drive is.

View the found files on the external hard drive once R-Undelete finishes searching for lost files.

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Fig.9. Found files

Now it is necessary to find the files you want to recover. R-Undelete gives you several ways to do that.

By sorting files by their types
R-Undelete presorts files by most common file types and places them to the corresponding tabs. For example, we may select the Pictures tab, if the most files we're going to recover are images. This tab has an additional and default option to display image files: tiles. Click the tab, select Tiles, and their size:

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Fig.10. Pictures tab

By manual searching for individual files or file groups:
You can also find files by searching for them manually. To do so, click the Search button, specify the file name or file mask, click the Start button, and only the matched files will be shown. File search is done on the files on the current tab. Select the All tab to search among all files.

For more detailed instructions for sorting and creating manual search, refer to the R-Undelete: File Search and File Sorting online help pages.

Viewing files:
You may use the built-in viewer to estimate chances for successful file recovery or to find the necessary file to recover. Right-click the file to view it.

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Fig.11. Picture view
Close the viewer to return to other files.

When your lost files are found, mark them for recovery:

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Fig.12. Files marked for recovery

4. Recover the marked files
After marking the required files for recovery, sufficient storage space on another disk should be available to save them.

Never save the recovered files on the place where they were located, or you may completely lose them!

Select the way R-Undelete saves the files: either into the file type folders or to the real folder structure.

When all the necessary preparations are made, click the Recover button to start file recovery.

If necessary, register R-Undelete. This procedure can be done on-the-fly even during file recovery operations. The program doesn't have to be restarted. Refer to the R-Undelete: Upgrade online help page for more details.

When R-Undelete finishes the process, it will display a brief report of its results,

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Fig.13. Recovery results

and the folder with recovered files will be automatically opened.

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Fig.14. Recovered files

File recovery from formatted disks or disks with partially damaged file systems
1. Open files on the required partition
Move the cursor over the necessary disk / partition and select Show files on the shortcut menu.

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Fig.15. Show files

You will usually not immediately find all the files you're looking for. Quite often you will see no files at all.

2. Deep scan the partition
Click the Deep scan button

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Fig.16. Deep scan button

and wait for R-Undelete to complete the scan.

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Fig.17. Deep scan progress
This may take a while, depending on how large your hard drive is.

3. Find lost files and mark them for recovery
View the found files on the external hard drive once R-Undelete finishes searching for deleted files.

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Fig.18. Found files

Now it is necessary to find the files you want to recover. R-Undelete gives you several ways to do that.

By sorting files by their types
R-Undelete presorts files by most common file types and places them to the corresponding tabs. For example, we may select the Pictures tab, if most files you're going to require are images. This tab has an additional and default option to display files: tiles. Click the tab, select Tiles, and their size:

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Fig.19. Pictures tab

By manual searching for individual files or file groups:
You can also find files by searching for them manually. To do so, click the Search button, specify the file name or file mask, click the Start button, and only the matched files will be shown. File search is done on the files on the current tab. Select the All tab to search among all files.

For more detailed instructions for sorting and creating manual search, refer to the R-Undelete: File Search and File Sorting online help pages.

Viewing files:
You may use the built-in viewer to estimate chances for successful file recovery or to find the necessary file to recover. Right-click the file to view it.

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Fig.20. Picture view
Close the viewer to return to other files.

When your deleted files are found, mark them for recovery:

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Fig.21. Files marked for recovery

4. Recover the marked files
After marking the required files for recovery, sufficient storage space on another disk should be available to save them.

Never save the recovered files on the place where they were located, or you may completely lose them!

Select the way R-Undelete saves the files: either into the file type folders or to the real folder structure.

When all the necessary preparations are made, click the Recover button to start file recovery.

If necessary, register R-Undelete. This procedure can be done on-the-fly even during file recovery operations. The program doesn't have to be restarted. Refer to the R-Undelete: Upgrade online help page for more details.

When R-Undelete finishes the process, it will display a brief report of its results,

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Fig.22. Recovery results

and the folder with recovered files will be automatically opened.

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Fig.23. Recovered files

Conclusion
All the examples above show that R-Undelete is a quite effective tool for recovering files from disks with damaged, deleted, formatted or even unsupported file systems. At the same time, such recovery is easy and doesn't require any deep knowledge of file recovery, as many file recovery programs do. Furthermore, R-Undelete recovers files from FAT/exFAT storage devices, like SD cards or external hard drives, without registration, that is, for free.