Understanding Deleted Files and What They Mean (2024)
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Attorneys who need to read and understand reports by computer forensics professionals and/or who need to present recovered files as evidence should understand how files are stored on computers and mobile devices, what happens when they are deleted, how they can be recovered, and know the limits on file recovery.
Before diving into the details of deleted files and how they are recovered, we need to understand how files are stored. Every computer storage device--hard drive, thumb drive, SSD, CD-ROM--has a "filesystem" that dictates how files are arranged and stored on that device. Filesystems maintain metadata about each file they store including the name of the file, the user who created or owns the file, the time it was created or modified, and the addresses or locations where the file is actually stored. They also divide their storage space into allocation units or "blocks" to make it easier to manage.
As an example, suppose I prepare my monthly budget using Microsoft Excel and save it as "Sep2017budget.xlsx". The metadata for the file might show that the file is owned by "Steven", was created at 12:00 PM on September 1, 2017, was last modified at 1:37 PM on
September 2, 2017 and uses 10 blocks of space starting at location 100,126 and another 8 blocks starting at location 255,211--a total of 18 blocks. As a user, I might be interested in the time stamps--e.g. to distinguish between drafts of a document--but I won't ever care what locations were used to store the file. When I open the file again using Excel, the program will read the data from these locations on my behalf so that I can view or edit the file. For data recovery, however, those locations are very important.
Microsoft Windows uses the NTFS filesystem. NTFS has a "master file table" or MFT that serves as a table of contents for a hard drive. When a file is created, a record is added to the MFT. When a file is deleted, the record associated with that file is NOT erased. Instead, it is flagged as available for reuse. When Windows creates or saves a new file, it will always look for an existing MFT record that is flagged for reuse before adding a new one to the table. What this means is that the record for a deleted file (including the name and list of storage locations) can potentially last for a long time.
When a file is deleted, the storage for that file is marked as "free" to show that it is unused or available. In most cases, this storage is NOT overwritten until another file is assigned to these locations. This means that the contents of a deleted file can also potentially last for a long time. The term "free space" refers to all of the storage locations that are not currently in use by any files. When a file is deleted, all of its storage locations become part of free space.
Writing or saving additional files will eventually cause the previous file contents and metadata to be overwritten. This is why it is important to preserve evidence early and not continue using a computer or device that may have recoverable data.
Data recovery and forensics software can recover deleted files (on Windows/NTFS) by looking for entries in the file table that have not been overwritten. If the entries are still in place, they will show the locations where the file was stored. If those locations have not been reused by a new file, the original file can be completely recovered. If some but not all of the locations have been reused, partial recovery may be possible. If all of the locations have been reused, recovery is not possible.
Other filesystems are similar to NTFS but there are differences. The FAT filesystem, often used for USB/thumb drives, does not have a master table like NTFS but stores the file names and starting locations separately for each directory. Unfortunately, FAT will only remember the starting location for a deleted file. Many files, especially large ones like videos, are stored in multiple pieces. This means that we will often only recover the first piece of a large file that was deleted from a thumb drive. The HFS+ filesystem, used on Mac and Apple devices, is much more complicated and frequently reorganizes its metadata so that it can be searched and used efficiently. This means that metadata for a deleted file on a MacBook will probably not survive as long as on a Windows PC.
If the metadata is gone, e.g. the MFT record for the file was reused, we may still be able to recover the file. Most file types--e.g. JPG, PDF, XLS--have specific formatting requirements which usually include a special "header" value and sometimes a "footer" to show the beginning and end of the file. In addition to searching the file table, most data recovery and forensics programs can recover deleted files by searching the free space (also called unallocated space) on a hard drive for the header and footer values associated with different types of files. This technique is called "carving".
Carving is not as reliable as using metadata to recover a file because we generally have to assume that the file was stored in one contiguous piece which is often not true. This can result in partial recovery where the end of the file is actually made up of data from a different file. For example, we might recover a video that will not play after the first twenty seconds or a picture where everything below the first half of the picture is visibly garbled.
There are times when deleted file recovery and/or carving are not possible. Disk encryption often prevents the recovery of deleted files. Mobile phones generally do not allow us to access free space or directly access metadata to attempt deleted file recovery. Many solid-state disk (SSD) drives implement a feature whereby storage locations that are marked for reuse are automatically zeroed out (overwritten with the number 0).
The recovery of deleted files can often add important evidence to a case. It's important to realize, however, that we are often missing information and should be careful about reaching conclusions that are unwarranted. When a file is still live, we can tell where it was stored and who owned it (e.g. "Sept2017budget.xlsx" is owned by "Steven" and stored in the "Finances" folder on Steven's desktop). When we recover a deleted file, even completely, we may not have the metadata that shows which directory or folder the file was stored in. If we use carving to recover a file from unallocated (free) space, we will not be able to show the time stamps for the file, who owned it, or what folder it was stored in. This is particularly important in cases that involve contraband (e.g. p*rnography in a work setting, in any setting). We should not assume that files carved from free space belong to the current user of the computer unless we have other evidence to support that.
Even on a computer that has only had a single owner, it's possible that files carved from free space were put there by someone else. For instance, they could have been downloaded by an employee at the store that sold the computer. Last year, I ordered a box of thumb drives. When I plugged in one of the drives, I discovered that it contained professionally-taken photos from a dance studio. A forensic examiner may be able to provide evidence to support the contention that carved files belonged to a particular user. For example, the examiner might show that the files are consistent with Internet searches conducted by that user or that the operating system cached thumbnail images of the same pictures.
Key points
If the metadata and data are still present, we can usually recover a file. If the metadata is missing but the data is present, we might be able to recover the file, at least partially, by "carving". If the data is not present, the file cannot be recovered.
We should not assume that files recovered from free space belonged to a particular user unless we have other evidence to support that notion.
Key terms
Filesystem: The manner in which files and storage are organized on a hard drive or other device.
File table: A list of files including their metadata and storage locations.
Free space: The area of a hard drive that is not currently in use by any files. May contain deleted files.
Carving: A method of recovering deleted files by searching free space for header and footer values for specific file types.
By Trace Digital Forensics, LLC Expert Website: http://www.tracedf.com Call (209) 769-2370
ABOUT THE AUTHOR: Steven Alexander Steven is the founder of Trace Digital Forensics, LLC and has over nineteen years of experience in Information Technology. He has a master's degree in Information Security specializing in Digital Forensics and several certifications including the EnCase Certified Examiner (EnCE) and Certified Information Systems Security Professional (CISSP).
Copyright Trace Digital Forensics, LLC
Disclaimer: While every effort has been made to ensure the accuracy of this publication, it is not intended to provide legal advice as individual situations will differ and should be discussed with an expert and/or lawyer.For specific technical or legal advice on the information provided and related topics, please contact the author.
When a file is deleted, the storage for that file is marked as "free" to show that it is unused or available. In most cases, this storage is NOT overwritten until another file is assigned to these locations. This means that the contents of a deleted file
deleted file
File deletion is the removal of a file from a computer's file system. All operating systems include commands for deleting files (rm on Unix, era in CP/M and DR-DOS, del/erase in MS-DOS/PC DOS, DR-DOS, Microsoft Windows etc.). File managers also provide a convenient way of deleting files.
A file that has been logically, but not necessarily physically, erased from the operating system, perhaps to eliminate potentially incriminating evidence. Deleting files does not always necessarily eliminate the possibility of recovering all or part of the original data.
When you delete a file, the operating system marks the area where that data resides on the hard drive disk (HDD) as available, and logistically removes it from the file tree structure. The magnetic data still resides on the disk, but the pathway to accessing the data has been removed from the operating system.
When you permanently delete a file, the storage drive makes its space available for new data. However, the file is not deleted. It remains on the hard drive; only the file pointers get deleted. (The File pointer shows you where the file exists and keeps track of it being accessed.)
Right-click the file or folder, and then select Restore previous versions. You'll see a list of available previous versions of the file or folder. The list will include files saved on a backup (if you're using Windows Backup to back up your files) as well as restore points, if both types are available.
By deleting them, you can free up some room for other files, applications, or updates. Another benefit of deleting installation files is to reduce clutter and confusion.
Yes.Police can recover deleted photos from iPhones/Android. Photo or image recovery is not impossible. There are many data recovery tools that not only police but also the general public can access to recover their lost data.
Yes, police can recover permanently deleted photos from a phone using special tools and software for mobile forensic investigations. However, the success of data recovery depends on several factors such as the type of disk, encryption, and file system used.
Cybercriminals and hackers can gain access to personal information stored in your computer even after you think you've deleted the files. This includes everything from financial documents to scanned images. If you think those files are gone because they've been deleted, think again.
Select the file you want to permanently delete and press Shift + Delete together. Windows will ask you to confirm. Click Yes. When you delete files through keyboard shortcuts, the entire “Recycle Bin” step is skipped.
You are not sure when a deleted file can be overwritten. So, there is no fixed answer to how long is too long before a deleted file is unrecoverable. You might discover that some files that were deleted years ago are still recoverable. But, some files that were deleted recently become unrecoverable.
Recycle bin is a waste-basket icon on desktop that works as a location or directory for deleted files or folders. All the files, folders, programs that are discarded get stored in it by default.
You can undo emptying the Recycle Bin by restoring your lost files through Windows File History. Just follow these steps: Open the Start menu and type “file history”. Choose the Restore your files with File History option.
You can recover deleted files in Windows 10 without third-party software by restoring them from the Recycle Bin: Double-click the Recycle Bin icon on your desktop. Select the deleted files you want to recover. Drag them from the Recycle Bin to any folder you want.
Untouched or unused files are disputable junk files. Unlike most system junk files that are automatically created, untouched or unused files are simply forgotten and take up space. It's good to be aware of these files and delete them from your Android device periodically.
Is Autorun a virus? Autorun.in is a virus that is usually spread through infected external devices like USB drives. Once an infected USB disk is introduced to your system, the virus can destroy your computer, self-executing files, destroying important documents, and replicating itself so that it is hard to remove.
Browse File Explorer, and once you find the file to be deleted, right click, and click on "Delete", or press the Delete key, or drag the file to the Recycle Bin. Provide confirmation if needed.
Files in trash will be automatically deleted after 30 days. You can restore files from your trash before the 30-day time window. You can also permanently delete them to empty your trash. If you delete, restore, or permanently delete multiple files or folders at once, it might take time for you to notice the changes.
1. In general, delete or remove refers to the act of eliminating a file, text, or another object from the computer hard drive or other media. For example, if you had a picture on the computer you no longer wanted, it could be deleted.
They sound synonymous but deleting and erasing a file are two different things. When you delete a file, you just reallocate it on the system making it harder to find, i.e., the files remain present in your system but are no more accessible. When you erase a file, it is gone forever.
What's the difference between delete and remove? This is a simple definition: Remove and Delete are defined quite similarly, but the main difference between them is that delete means erase (i.e. rendered nonexistent or unrecoverable), while remove denotes take away and set aside (but kept in existence).
In conclusion, how far back text messages can be retrieved can vary based on the type of phone and app being used, but they can generally be accessed for up to 10 years.
So, can police recover deleted pictures, texts, and files from a phone? The answer is yes—by using special tools, they can find data that hasn't been overwritten yet. However, by using encryption methods, you can ensure your data is kept private, even after deletion.
Cellebrite is a full suite of professional forensic data recovery tools ideal for solving crime cases. Combined with BlackLight and Cellebrite Digital Collector, it offers a faster and unmatchable file extraction process for Windows, Mac, Android, and iOS.
Deleted data recovery is often called the “bread and butter” of digital forensics, and in truth, a lot of digital forensic cases involve deleted data recovery.
This technology is primarily used to aid in criminal investigations. However, the catch here is the word "remotely". The fact is, in most jurisdictions, police cannot remotely access your phone without a warrant or your explicit consent.
In technical terms, your deleted browsing history can be recovered by unauthorized parties, even after you cleared them. Why is it so? Let's explore how Windows deletes confidential information and you'll know the answer in a short while. But first, let's have a look at what browsing history actually is.
Damaged or corrupted recycle bin application could be causing the files to reappear after deletion. This could cause your deleted files to reappear in the Recycle bin upon refreshing the window. This can be fixed using the CMD (administrator).
How to permanently delete files from Windows 10. To permanently delete files on Windows, send them to the Recycle Bin and then empty the Recycle Bin to delete them for good. Once the bin is empty, you can't recover the files unless you have data or file recovery software.
The recycle bin is a holding place for deleted files. To permanently delete a file, you can delete it again from the Recycle Bin, or you can empty the Recycle Bin. It is recommended you empty the Recycle Bin every once in a while to free up space.
Where do deleted files go if they are not there in the Recycle bin? Although files are deleted from the Recycle Bin, they still physically exist on the hard drive. They remain there until overwritten by new data. Once overwritten, the only recovery method is by using backup storage media.
Go to Settings > System > Storage.Then, select This PC and click on Temporary files and recycle bin.In the new window find and click the option Empty recycle bin.Press Delete to confirm.
Turn off Storage Sense. To solve the "my computer is automatically deleting files in Windows 10" problem, you can turn off the Storage Sense feature in Windows 10. This feature will automatically delete unused files and temporary files as well as old files in the Downloads folder and Recycle Bin regularly.
Malware. Malicious software, particularly worms, can run rampant on a storage device and start deleting files. Other malware like viruses can cause files to disappear because when they try to rewrite a file during the infection process they may cause write errors that corrupt the file.
You can undo emptying the Recycle Bin by restoring your lost files through Windows File History. Just follow these steps: Open the Start menu and type “file history”. Choose the Restore your files with File History option.
Is Autorun a virus? Autorun.in is a virus that is usually spread through infected external devices like USB drives. Once an infected USB disk is introduced to your system, the virus can destroy your computer, self-executing files, destroying important documents, and replicating itself so that it is hard to remove.
The reasons for the computer restarted and deleted everything are various, like human error, virus attack, software conflict, corrupted system files, power failure, and more. When being caught in such a problem, you may be eager to know how to retrieve missing files after reboot.
When Windows deletes a file, it moves it to a specific hard drive sector and hides it from the operating system. Even after emptying the Recycle Bin, there is still a chance of data recovery if no new data is written on those specific sectors where the deleted files exist.
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