Quick Answer
Yes, wiping a hard drive will remove the operating system along with all other data stored on the drive. Wiping or reformatting a hard drive resets it to a factory-like blank state with no files, folders, installed programs or operating system. However, with the right forensic data recovery tools, it may be possible to recover remnants of some deleted files after wiping a drive.
What Happens When You Wipe a Hard Drive?
Wiping or reformatting a hard drive erases all of the data on the drive by overwriting it with zeros or random data patterns. This removes all files, installed software, the operating system, system settings and any other data stored on the drive.
Essentially, wiping a hard drive returns it to the same blank state it was in when it was brand new. At this point, you would need to reinstall an operating system before being able to use the hard drive again.
Low-Level vs High-Level Formatting
There are two main methods for wiping a hard drive:
Low-level formatting – Also known as zero-filling, this process overwrites all sectors on the disk with zeros. It eliminates all data including partitions, file systems, operating systems, hidden sectors and any other software or files on the drive.
High-level formatting – This resets the file system and partitions on the drive but does not overwrite the existing data. It simply resets the index of where data is stored so that the files appear deleted. The actual data still remains on the drive until it gets overwritten by new data.
For securely wiping a hard drive, low-level formatting is necessary to overwrite all existing data. High-level formatting alone is not sufficient.
Why Wipe a Hard Drive?
There are a few key reasons you may want to completely wipe or format a hard drive:
- Remove all personal data before disposing of, selling or giving away a computer
- Eliminate viruses or malware that may resist being removed by antivirus software
- Clear out old or unnecessary data before a clean OS installation
- Reset the drive before performing diagnostics tests
- Start fresh with factory settings when troubleshooting drive errors
Wiping the drive helps ensure no sensitive files or software remain that the next user of the drive could access.
Will Formatting Remove Operating System?
Yes, formatting a hard drive will remove the operating system along with all other data on the drive.
When you format or wipe a hard drive, everything is erased including:
- Operating system files (Windows, Mac OS, Linux distributions)
- Preinstalled software or bloatware
- Installed applications and programs
- Personal files and folders
- System settings and preferences
- File allocation table / file system
- Boot sector
The operating system needs to interact with the hard drive via the file system and boot sector. When these are wiped, the OS loses its connection to the drive.
Without an operating system, the computer essentially returns to bare metal hardware. You would need to reinstall an OS to use that formatted hard drive again.
Can Deleted Files Be Recovered After Wiping a Hard Drive?
In most cases, no. Wiping a hard drive removes all files and makes direct data recovery impossible. However, advanced forensic data recovery methods may be able to recover remnants of some deleted files.
When data is deleted or a drive is formatted, the actual contents are not removed right away. The space they occupied is just marked as available to be overwritten. Until those sections are overwritten, data recovery software can scan for file fragments that may still be present.
However, deliberately wiping a hard drive overwrites all sectors, leaving virtually no remnants behind. Only a very small portion of data may potentially be recoverable by forensic experts with specialized tools.
Some key points on data recovery after wiping a hard drive:
- Basic personal recovery software will not work, as all file indexes and metadata are removed.
- Most data is unrecoverable, as the original content gets overwritten by zeros or random data patterns.
- Fragments of files could exist in sectors not overwritten due to bad sectors or remapped sectors.
- Forensic recovery requires expensive professional lab equipment to read raw data platters.
- Recovery likelihood and amount depends on the wipe method used.
While there is a slim chance of recovering traces of data, wiping a drive makes this extremely difficult, costly and unlikely for most people.
Steps to Wipe a Hard Drive
If you want to completely wipe your hard drive clean, here are the general steps:
- Back up any important data. Ensure you have copies of any files you need to save before wiping the drive.
- Boot into the BIOS. Access the system BIOS setup utility on startup.
- Change boot order to removable media first. This will allow you to boot from the DVD or USB drive.
- Insert wiping software boot media. Insert DVD or USB drive containing drive wiping utility.
- Boot from the disk. Restart the computer and boot into the wiping software.
- Select wiping method. Choose to wipe with zeroes, random data or multiple passes.
- Select drive to wipe. Choose the target hard drive to erase.
- Start the wipe process. Commence overwriting the hard drive.
- Reinstall OS. Once complete, reinstall your operating system.
Be extremely cautious when wiping a drive, as the process is not reversible once started.
Most Effective Wipe Method
The most effective wipe method is to use multiple passes with both zeros and random data patterns:
- First pass – Overwrite entire drive with zeroes to remove existing data.
- Second pass – Overwrite with random data to eliminate remnants of file structures.
- Additional passes – Additional overwriting further reduces recoverability.
The more overwrite passes, the less likely data could potentially ever be recovered by any means. 3-7 passes are generally recommended for thorough wiping.
Some key pointers on effective drive wiping methods:
- Use low-level formatting, not just high-level quick format.
- Overwrite entire drive surface, not just partitioned space.
- Use multiple passes for higher security.
- Alternate zeroes and random data between passes.
- Check drive for defects or bad sectors which may retain data.
- Wipe all sectors including service areas and hidden sectors.
Combining multiple overwrite passes with different bit patterns ensures all recoverable data remnants are eliminated.
Recommended Drive Wiping Software
Here are some top options for securely wiping hard drives:
| Software | Details |
|---|---|
| DBAN | Darik’s Boot and Nuke, free open source tool, simple interface |
| Active@ KillDisk | Bootable toolkit includes drive wipe feature, 7+ overwrite methods |
| Parted Magic | Linux distro with GUI tools for drive wiping and partitioning |
| HDDErase | Free boot utility from Hitachi for external erasure |
| KillDisk | Secures wipes all data with a variety of standards |
| Mac Disk Utility | Built-in tool to securely erase external drives on Mac |
These tools allow selecting from a variety of data sanitization standards to securely overwrite hard drives.
Can You Recover Files After Formatting Hard Drive?
If a hard drive was only quickly reformatted, some files can potentially be recovered. However, if the drive is fully wiped with multiple overwrites, file recovery becomes virtually impossible.
When a drive is formatted using the fast “Quick Format” option, the files are not actually erased. Only the file allocation table marking them as deleted is modified.
Recovery software can scan the drive and often recover these marked but not overwritten files. However, if a full wipe process was performed, no files can be restored.
When Formatting Allows File Recovery
Files can potentially be recovered after formatting only if:
- The quick format option was used.
- Drive sectors have not been overwritten.
- Drive was formatted, not wiped.
- Only the file table was reset, not all data.
In these cases, data recovery software may be able to recover files by scanning the raw drive platters. But with the right tools, drives can be wiped to prevent any file restoration.
When Formatting Prevents File Recovery
Files cannot be recovered after formatting if:
- A full low-level format was performed.
- Drive was wiped with multiple overwrite passes.
- All sectors and spaces have been overwritten.
- Secure wipe utility was used.
- Degaussing or physical destruction was used.
With proper use of drive wiping tools and multiple pass overwrites, file recovery becomes impossible by any means.
Can a Wiped Hard Drive Be Restored?
No, a wiped hard drive cannot be restored to recover lost data or operating systems. The only option is to reinstall software and start over with a blank drive.
When a wipe utility overwrites all of the sectors, it permanently destroys the existing data. Even advanced forensic recovery techniques cannot reliably restore wiped files.
After wiping a drive, reverting it back to the previous state is impossible. However, some options after wiping a hard drive include:
- Reinstalling the OS to use the blank drive again.
- Initializing and formatting partitions before reusing.
- Running diagnostics to check for and repair any bad sectors.
- Checking drive health before restoring personal files.
- Ensuring no confidential data remains through inspection.
While the wiped drive cannot be restored, proper steps can be taken before reuse to ensure performance and security.
Do Department of Defense Wipes Work?
U.S. Department of Defense data wiping standards are considered quite effective when done properly. The DoD 5220.22-M standard specifies a 3-pass overwrite procedure to sanitization disks.
This involves:
- Overwriting all data with zeros in the first pass.
- Overwriting with 1s in the second pass.
- Overwriting with a random bit pattern in the final pass.
Government testing found this 3-pass method reduces data recoverability to effectively zero for any current technology.
However, some consider this standard outdated as it was established in the 1990s. Modern techniques use more passes and alternating bit patterns for even higher security.
The latest government standards specify a 7-pass overwrite or physical disk destruction to better guard against future data recovery technology. While the DoD method is still effective, best practices evolve over time.
Conclusion
Wiping or formatting a hard drive removes all data including the operating system by overwriting it with zeros or random bit patterns. This resets the drive to a blank state requiring OS reinstallation before reuse. While traces of deleted files could potentially be recovered using advanced forensics, wiping the drive makes this extremely difficult and prohibitively expensive. Following proper data sanitization standards when wiping hard drives ensures no usable data remnants remain.