Lost Data? What to Do and How to Recover Your Files
What to Check First — and How to Avoid Making Data Recovery More Difficult
Have important files disappeared from your computer, external hard drive, USB drive or memory card?
Data loss does not always mean that your files are permanently gone. The situation can range from accidentally deleted files to a failing drive, damaged hardware, corrupted partitions or a serious file-system problem.
What you do immediately after data loss can be important. Continuing to use the affected storage device, formatting it or installing software onto it may overwrite information that could otherwise be recoverable.
In this guide, we explain what to do first, what to avoid, and when professional data recovery may be appropriate.
Common Data Lost Issues
Files were accidentally deleted
Files or folders disappeared or cannot be found from their usual location.
This may indicate that the files or folders have been accidentally deleted, moved, or become hidden. Before attempting data recovery, check your backup, Recycle Bin, and File History. If you use a cloud storage service such as Microsoft OneDrive, also check its online Recycle Bin and previous file versions, as there may be a good chance of restoring the missing data.
If you still cannot locate or restore the files, a professional data recovery tool or service may be able to help. Please feel free to contact us if you need further assistance.
The drive is detected but files are missing
When the power is on, the hard drive appears but it displays "...is not accessible", or the system pops up "You need to format the disk in drive X: before you can use it."
This usually indicates a minor hardware or logical issue with the hard drive, rather than a problem with the circuit board (PCB). In many cases, the data may be recoverable using professional data recovery software.
However, attempting recovery yourself can carry a risk of further data loss, particularly if the drive has an underlying hardware problem. If the data is important, it is recommended to seek professional assessment before proceeding with recovery attempts.
The hard drive is not detected even in computer startup
Computer cannot detect the hard drive even in its booting or BIOS.
This usually indicates a hardware-related problem with the hard drive. As a first step, if possible, try loading the BIOS default settings and check whether the drive is detected normally.
If the problem persists, avoid making further changes to the drive or computer BIOS settings. Instead, please seek professional assistance to properly diagnose the issue and minimise the risk of data loss.
The hard drive spins but makes unusual clicking noises
When power on, the hard drive spins but makes unusual clicking noises.
This may indicate a serious physical problem with the hard drive. While a faulty circuit board (PCB) can sometimes cause similar symptoms, a problem with the internal read/write heads is often a more likely cause.
IMPORTANT: Please stop powering on or repeatedly attempting to use the drive, as further operation may increase the risk of permanent data loss. If the data is important, we strongly recommend seeking professional data recovery assistance as soon as possible.
The computer says the drive needs to be formatted
Hard drive is detectable, but files are not accessible
This usually indicates a file system or partition problem, although a developing hard drive hardware issue can also cause the computer to incorrectly report that the drive needs to be formatted.
IMPORTANT: If the drive contains important data, do not click Format or initialise the drive, as this may make data recovery more difficult. The drive should be properly diagnosed first, and professional data recovery may be required if the file system or drive structure has been damaged.
Files became inaccessible after a crash or power failure
Files are not accessible after a crash or power failure
This may indicate file system or data structure corruption caused by an unexpected system crash, power failure, or improper shutdown. In some cases, the underlying hard drive hardware may also be affected or already have an existing fault.
IMPORTANT: If the files are important, avoid repeatedly accessing, repairing, or modifying the drive until the cause has been properly diagnosed. Further changes may make data recovery more difficult. Professional assessment may be required to recover the files safely.
Hard Drive is Physically Damaged
The hard drive was dropped, damaged or exposed to liquid
This may indicate physical damage to the hard drive caused by a drop, impact, liquid exposure, or other external damage. Depending on the severity, the damage may affect the circuit board, internal components, read/write heads, or other mechanical parts.
IMPORTANT: If the drive contains important data, please do not power it on or attempt to open, repair, or dry the drive yourself. Further operation may cause additional damage and reduce the chances of successful data recovery. Professional assessment is strongly recommended, particularly after physical or liquid damage.
Common Causes of Data Loss
- Accidental deletion — Files or folders may have been deleted by mistake.
- Formatting — A drive or partition may have been formatted before important files were copied elsewhere.
- Failing HDD or SSD — Storage hardware can develop faults that make files inaccessible.
- File-system or partition corruption — A damaged file system or partition table can make a drive appear empty or unreadable.
- Physical damage — Drops, liquid damage, electrical faults or damaged circuit boards can affect storage devices.
- Power failure or improper disconnection — Unexpected shutdowns or removing removable storage while it is being written can cause corruption.
- Malware or ransomware — Malicious software can delete, encrypt or otherwise make files inaccessible.
- Overwritten data — New data written to the affected storage area can reduce the chance of recovering deleted files.
What to Do When Important Data Is Lost?
On Windows
Including Windows7, Windows10, Windows11 and so on, whether running on a Desktop PC, Laptop, All-in-one Computer or Tablet.
On Windows — protect the affected drive first:
1. Stop unnecessary use- Stop saving new files to the affected drive.
- Do not install recovery software onto the same drive containing the lost data.
- If the drive is making unusual noises or repeatedly disconnecting, stop using it.
- Check the Recycle Bin if files were recently deleted.
- Check whether the files are available in a known backup or cloud-sync location.
- Check whether the drive and its partitions are still detected in Disk Management.
- Do not format the drive simply because Windows asks you to.
- Do not repeatedly run repair or recovery operations on a physically failing drive without considering the data first.
- If the data is important and the drive is failing, damaged or not detected, stop and have the situation assessed before further testing.
On a Mac
Including macOS versions such as Ventura, Sonoma, Sequoia and Tahoe, whether running on a MacBook, iMac, Mac mini, Mac Studio or other Mac computer.
On a Mac — protect the affected drive first:
1. Stop unnecessary use- Stop copying or downloading new files to the affected storage device.
- If the drive is making unusual noises or repeatedly disconnecting, stop using it.
- Do not install recovery software onto the same storage device containing the lost data.
- Check the Trash if files were recently deleted.
- Check Time Machine or another known backup if one exists.
- Use Disk Utility only to check whether the storage device is detected; avoid erasing it if the data is important.
- Do not erase or reformat the drive just because macOS reports a problem.
- If the storage device has physical symptoms, avoid repeated attempts to access it.
- If the data is important and the drive is failing, damaged or not detected, stop and have the situation assessed before further testing.
When Should You Stop Troubleshooting?
- The hard drive or SSD is not detected.
- The hard drive is clicking, grinding or making other unusual noises.
- The drive repeatedly disconnects or becomes extremely slow.
- The computer reports that the drive needs to be formatted.
- Important business, family or irreplaceable files are involved.
- The storage device has suffered a drop, liquid spill, electrical event or other physical damage.
- You are unsure whether a repair action will overwrite or erase the data.
- You have already tried recovery or repair software without success.
Common questions
Can deleted files be recovered?
What should I do first after losing important data?
Should I format a drive if Windows says it needs to be formatted?
Can I run CHKDSK or Disk Utility First Aid on a failing drive?
What if my hard drive is making clicking noises?
Can you recover data from a damaged or undetected hard drive?
Don’t Make Data Loss Worse!
When important data disappears, it is tempting to try every repair or recovery option immediately. That can sometimes make the situation worse.
Do not format the drive, reinstall an operating system, copy large amounts of new data onto the affected drive, or repeatedly operate a drive that is making unusual noises when the files are important.
For deleted files, continued use can overwrite the storage space that may contain the deleted data. For a physically failing drive, repeated operation can also make an existing hardware problem worse.
If the files are important, stop and get the storage device assessed before taking actions that could change the original data.