Most corruption is damage to the map rather than the data. The “map” is essentially the entry describing where a file lives, not the file itself. This is one reason that so much of this type of corruption is recoverable; it is also why allowing a repair program to “clean up” the volume will usually result in making what would have otherwise been recoverable into something you will never get back again.
Repair programs like chkdsk and Disk Utility do not intend to save your data; they mean to create consistency in your file system by discarding those entries which they cannot reconcile. Copy everything off that you still can read before allowing anything to attempt to repair the disk.
Although these may seem the same to the user who is experiencing them, they require entirely different treatment.
Whether you will be able to use a file that has been partially damaged will depend mostly upon what type of file it is.
Since Office documents and ZIP archives are simply compressed container type files, damage of even part of either typically results in entire files being unable to open; however, due to documentation of file structures, you may be able to recover the parts that remain undamaged, repackage them & attempt to use those again. Photographs and video, on the other hand, will continue to function or render to an extent with some lost data. For example, if a JPEG image has a damaged end segment, it should still show to some extent. Similarly, the video portion of a damaged file may still be playable, since a damaged container can still have content within it, which can then be remuxed (repackaged) into another container file format where it could potentially be played back all the way through to the point of the original damage, or possibly further than that.
Databases are much less tolerant of error than all other file types: a single corrupted page at the wrong location can render the entire file unable to be mounted, and therefore repair requires an understanding of the internal structure of the file, rather than its content. Plain text, CAD and RAW images are generally very good about recovering their content because typically the area affected by a problem (eg. disk sector) has boundaries that do not spread throughout the rest of the file.
Of course, as elsewhere, the order in which you address these problems is important; however, this is one of those places where your “standard” methods for repairing errors may represent greater risks than they would in most other cases.
Widespread corruption on the part of the drive usually indicates a hardware failure (a disk drive experiencing bad sectors). Isolated failures that occur during a system failure are rarely due to bad sectors and are thus unlikely to have been caused by physical damage to the media. Your diagnostic will determine whether widespread corruption has occurred prior to even attempting to fix anything.
Before any attempts are made to fix a damaged drive, a clone of the original drive is created. Therefore each subsequent attempt to correct the issues will be done using a copy of the original drive and no changes can be made that cannot be reversed.
File systems like NTFS use a master file table (MFT), APFS uses a series of checkpoints, and ext* uses a superblock that contains information necessary to mount the partition. When a sufficient number of these items survive intact, they are used to reconstruct the lost metadata which includes filenames and directories. If successful, the data itself also becomes accessible again.
When a file system is irreparably damaged (unrecoverable), files will be recovered using content signatures, with names & folders lost.
Recovered files are opened within their respective application. Any items that remain unrecoverable can be described by name instead of returning an empty file with no applicable association.
Pricing based upon the number of devices being recovered, not on the amount of files recovered.
Price per device: single drive/SSD/external = from £300 +VAT; memory cards / USB sticks = from £250 +VAT; RAID/NAS/server volumes = from £500 +VAT. Written quote & free 48 hour diagnostic prior to any recovery work. In addition, in most cases you only pay if we recover your data.
Identify which files are important. The ability to verify what’s been successfully recovered during a partial recovery is considerably more valuable than handing over numerous files and expecting you to sift through them.
Before we can start work on your unit you will need to send it in for a free diagnostic review and tell us briefly what happened. We then have one of our engineers review your unit & verify your exact quote in writing prior to starting any work.
Before dropping off or posting your device please request a quotation either by telephone or using our quotation form. The first step to recover your data is to get the device to us. Please ensure that you pack the device securely, include your contact information and then forward it to us. Once we have completed the free diagnostic of your device we will provide you with your exact price in writing prior to commencing any further work.
Posting it? We would suggest using a tracked and insured delivery method. Want to drop it off? That’s okay too. Monday to Friday, from 9am to 5:30pm is good; no appointment necessary: simply prepare the item as described above.
If you want a few more details first, fill out this form and let an engineer go through it and send you back a custom quote.
We’ll be in touch shortly. If it’s urgent, call 01865 593000.
What most users are interested in when it comes to retrieving data from damaged media/drives.
In general, isolated damage after a failure of some kind or due to improper removal is usually a file system issue. Problems with all files as time progresses, or a drive that is getting slower indicates bad sectors spreading, which means you have a hardware issue. This is determined by our complimentary diagnostics prior to doing anything else.
Not before you copy off what still reads: chkdsk will correct your file system, but will not restore your files. If chkdsk cannot resolve the inconsistency it will either delete/truncate the item. Doing this on a failing drive may be the #1 way to guarantee permanent loss of data.
Most likely you received an error stating that Windows could not find your file system. This is usually because there was damage to your boot sector and/or master file table, not because your files are gone. Do not agree to format: this will write a new file system over the existing one that recovery efforts would use.
The tolerance of file types to loss varies greatly. While photographs and videos typically will continue to function with minor loss (even some missing frames), Office document and archive files are very much compressed “containers”. Loss of even one byte within such an archive container may render the entire file unusable, however individual sections of intact content can frequently be recovered. Databases, due to their high degree of interrelatedness, are generally the least tolerant to loss.
Yes, if we can rebuild your file system. In instances when the file system cannot be rebuilt, files are usually “carved” via signature, i.e., the contents of each file will restore to correct order, although they will be assigned sequential names without respect to the original directory structure. During our diagnostic process we’ll advise as to whether carving, or rebuilding will apply to your specific situation.
Our costs begin at £300 +VAT per unit for single drives, while pricing begins at £250 +VAT for cards/USB sticks, and starts at £500 +VAT for RAID/NAS/server volumes. Your costs will always be clearly stated in writing once a no-cost 48 hour diagnosis has been completed.
We offer a no-charge diagnostic service and data recovery from all drives/sticks/cards. In most cases you only pay if we recover your data. Do not attempt to use any repair software; let us help you recover your data today.