When a file is deleted from your computer, it may seem like it’s gone for good. However, the reality is more complex. Whether or not a deleted file can be recovered depends on several factors.
What happens when you delete a file?
When you delete a file, either by hitting delete/backspace or emptying the Recycle Bin, it is not immediately erased from your hard drive. Instead, the operating system marks the space occupied by the file as available for new data. The contents of the file still physically exist on the drive until that space is overwritten by something else.
This is because, for performance reasons, operating systems do not actually erase the data when you hit delete. If it had to overwrite every byte after each deletion, your computer would become very slow each time you tried to delete larger files. So instead, it simply marks the space as ready to be used again.
File recovery is possible until data is overwritten
As long as the original contents still reside untouched on the drive, recovery is possible using specialty data recovery software. This software scans the drive and looks for files that have been marked for deletion. When it finds them, it can rebuild the file structure so the files become accessible again.
However, once new data has been written to the same sectors on the hard drive, recovery becomes difficult or impossible. Some fragments of files may still be retrievable if only part of the file was overwritten, but recovery success rates drop dramatically the more new data occupies the space.
Your operating system and storage device affect recoverability
The recoverability of deleted files depends on both your operating system and the type of storage device you use.
Operating system factors
- Recycle Bin – Files deleted from the Recycle Bin have an extra level of recoverability until the Recycle Bin is emptied.
- Secure delete – Some operating systems like Linux and macOS have “secure delete” options that deliberately overwrite data to prevent recovery.
- Disk optimization – Features like disk defragmentation redistribute files across the drive, making overwritten sectors harder to locate.
Storage device factors
- Hard disk drives – Due to their magnetic storage, recovery success rates are relatively high on HDDs until data is overwritten.
- Solid state drives – SSDs spread data randomly across solid state cells, making targeted recovery more difficult.
- File system – The file system manages how and where data is physically stored. Some (like NTFS) store more recoverable metadata than others (like FAT32).
Manual deletion techniques that prevent recovery
If you want to ensure a file is permanently deleted beyond any hope of recovery, you need to manually override the normal deletion process. Here are some techniques that can accomplish this:
Use wiping software
File wiping utilities are designed to overwrite the space used by your files multiple times with different bit patterns to completely obscure the original data.
Format the drive
Formatting a hard drive erases all its data by initializing a new blank file system. This overwrites all sectors on the drive.
Perform a secure erase
SSDs and other flash memory devices often have built-in secure erase commands that instruct the device to physically reset all data.
Physically destroy the drive
If you want to be absolutely certain, destroying the physical drive platters eliminates any chance of recovery.
Recovery from backups or snapshots
Even if you manually overwrite a file beyond recoverability on your live system, copies of that data may still exist elsewhere.
- Backups – If you have backups that snapshotted your drive before you deleted the files, they may be restorable from there.
- Versioning – Source control systems or cloud storage services with versioning can potentially restore older copies of files.
- Cached copies – Your operating system, antivirus software, search indexes or other programs may have made cached copies that still exist.
Can permanently deleted data be recovered from an SSD?
Recovering deleted files from an SSD is more difficult than a traditional hard disk, but not always impossible.
Because SSDs spread data across many independent flash memory cells, securely erasing individual files is tricky. When you delete a file it’s unlikely any full blocks get wiped and overwritten. Different parts of the file end up in different locations.
However,recovery software can scan the entire SSD contents at a low level to identify and reconstruct partially overwritten file fragments. The more new data that’s written, though, the less likely this becomes.
An SSD’s controller will also routinely perform its own cleaning and consolidation operations. This actively erases stale data blocks no longer in use and writes their contents elsewhere. This automatic block wiping can gradually render deleted file fragments unrecoverable.
Secure erase is the most effective option
To fully delete a file beyond recovery on an SSD, use the controller’s built-in secure erase feature. The SSD will be instructed to reset all data blocks to their factory state, obliterating any trace of existing files both live or deleted.
Alternatively, encrypting your SSD before writing any sensitive files also ensures permanent data erasure if you discard the encryption key.
File recovery from RAM
Recovering deleted files from RAM is only possible while the system remains powered on and the memory contents intact. Once powered down, any files that existed solely in the computer’s memory are gone for good.
RAM operates differently from hard drives in how it stores data. It does not overwrite deleted content with new data but simply marks the associated memory addresses as available again. So while the computer is still running, forensic tools can scan RAM for recognizable file fragments.
The chances of RAM file recovery depends heavily on how much free memory space is available. The more free memory, the higher likelihood that old data persists unoverwritten. On systems low on free RAM, recovery becomes unlikely.
Possible recovery scenarios
- Recovering temporary files or caches that only existed in RAM and were not committed to disk.
- Recovering files left open and auto-saved to RAM by some applications.
- Accessing encrypted files by capturing decryption keys stored in memory.
In general, the ephemeral nature of RAM means files solely stored there are not recoverable once the machine is powered down.
Recovering deleted files from the cloud
If you store files in the cloud rather than locally, they cannot be manually deleted in the traditional sense. However, many cloud services offer versioning or timed data retention policies that can mimic deletion after a certain period of time.
Cloud file deletion nuances
- Deleted files may get temporarily archived in backups before permanent erasure.
- Deleted cloud account data may remain recoverable for a time after account cancellation.
- With versioning enabled, older copies of deleted files can be restored.
To ensure permanent deletion from a cloud service, you must:
- Turn off versioning/backups and set shortest retention timeframes.
- Ensure old copies are purged from their archives.
- Request permanent erasure by customer support if possible.
Multi-tenant cloud architectures can also make it impossible to guarantee deleted file irretrievability if no physical destruction occurs.
Can you recover permanently deleted files from the Recycle Bin?
When you delete a file in Windows, it gets sent to the Recycle Bin unless you bypass it. The Recycle Bin provides a second change, allowing you to restore accidentally deleted files.
Files in the Recycle Bin remain recoverable even though they are marked as deleted. Their data still resides in its original location on the hard drive. The contents only get overwritten once the Recycle Bin is emptied.
So if you act quickly while the file remains in the Recycle Bin, you can right click on it and select Restore to retrieve it. However, once you empty the Recycle Bin, Windows considers those files permanently deleted.
Alternative methods after emptying the Recycle Bin
If you only recently emptied the Recycle Bin, recovery software may still be able to restore its files by searching the hard drive’s unallocated space. But if significant new data has been written, overwriting the deleted contents, then recovery becomes impossible.
For this reason, it’s critical to avoid writing new data to the drive if you need to recover a file mistakenly deleted from the Recycle Bin. Install recovery software before doing anything else.
Can you recover old email messages that were deleted?
Recovering old deleted emails depends on the email service and client in question. But often at least partial recovery is possible.
Webmail services
For webmail (Gmail, Outlook.com, Yahoo Mail etc), your options are:
- Check the Trash – Recently deleted emails may still be in your account’s Trash folder
- Undo Send – Some services let you undo sent email for a short window.
- Cloud backups – Deleted emails may exist in periodic account backups.
Email clients
With local email clients (Outlook, Thunderbird etc), deleted emails typically move to a local Trash folder. They remain recoverable from there until that local Trash is emptied.
Email server data backups
The email server itself may retain deleted message backups in archives or mailboxes. Admins may be able to recover email from there.
But overall, once deleted emails are removed both locally and from the cloud, complete recovery becomes unlikely.
Can you recover a deleted Facebook message?
Recovering deleted Facebook messages is difficult but sometimes possible in limited circumstances:
- Request archive – You can request an archive of your Facebook data. Deleted messages may still be retained for a time in their archives before permanent erasure.
- Messenger History – The Facebook Messenger app has a Message History option that lets you search for deleted chats on mobile devices or desktop.
- Backups – Messages may exist in device or cloud backups your phone made before deletion.
However, Facebook does not provide a build-in undeleting feature. Your ability to recover deleted messages largely depends on their backups existing somewhere.
Facebook also wipes accounts permanently after 30 days of requested deletion. Messages linked solely to that account would be permanently gone at that point.
Can you recover permanently deleted text messages?
Recovering deleted text messages depends on your phone model and platform.
iPhone text message recovery
For iPhones, text recovery requires having previously created an iTunes or iCloud backup that contains the messages before they were deleted.
Without an existing backup, text messages deleted from an iPhone are typically gone for good. However, some third-party tools may be able to extract texts still stored in the device’s local database.
Android text recovery
On Android devices, the best chances of text message recovery are:
- Using the device’s built-in restore features to restore an old backup.
- Using an app like SMS Backup & Restore to extract texts from a phone’s database.
However, once text messages are permanently deleted from both the device and any cloud backups, recovering them becomes very difficult.
Permanently deleting files – techniques compared
Here is a comparison of various techniques for permanently deleting files beyond any chance of recovery:
| Method | Ease of use | Security level |
|---|---|---|
| Wiping software | Easy | High |
| Drive format | Moderate | High |
| Secure erase (SSDs) | Moderate | Very high |
| Physical destruction | Hard | Guaranteed |
As you can see, options like drive formatting and secure erasure provide the best balance of security while still being reasonably easy to perform.
Deleted files vs deleted accounts
It’s important to distinguish between deleted files and deleted accounts online. Even if you delete all files in an account, remnants may remain recoverable if the account itself still exists.
Most online services retain deleted account data for a period of time after closure. Permanent irretrievable erasure of associated files typically only happens after:
- The account is deleted/closed.
- A sufficient retention period has passed.
- Backups are overwritten or retired.
So for ultimate file deletion assurance, closing online accounts entirely is recommended, not just removing files.
Mitigating risks from deleted file recovery
If you wish to ensure deleted files stay private, here are some tips:
- Use platform-specific secure deletion methods when available, like SDelete on Windows.
- Encrypt sensitive files before deletion to prevent usable recovery.
- Frequently wipe free space on your drives with sdelete to obscure deleted file fragments.
- Physically destroy drives storing sensitive files you want completely erased.
Practice proper security hygiene to minimize your exposure from unwanted recoveries.
Conclusion
While deleted files can often be recovered, actual permanent erasure does eventually occur through overwriting or physical destruction. But you shouldn’t rely on normal deletion methods for secure data removal. Use proper tools and techniques instead.
Understanding the nuances around file deletion, drive architectures, backups and versioning can help guide your expectations for recoverability. But when in doubt, assume deletion does not guarantee complete data destruction.