Putting a hard drive in a freezer is actually a technique that some people use to try and recover data from a failed or failing hard drive. There are a few reasons why this method could potentially work.
Low temperatures can help recover data
One of the main reasons people put a hard drive in a freezer is that low temperatures can potentially help recover data from a failed drive. Hard drives consist of very small mechanical parts that are precisely aligned. When a hard drive fails, it is often due to the mechanical parts malfunctioning or becoming misaligned due to overheating. By cooling the drive down to very cold temperatures, it can cause the mechanical parts to contract back into their proper positions, realigning the platters and read/write heads inside the hard drive. This allows the drive to temporarily function again, potentially long enough to copy data off of it.
In addition, low temperatures reduce thermal stresses on the components inside the hard drive. Excess heat can cause further warping or damage to the delicate internal parts. The cold temperatures act as a preservative, reducing the chances of continued damage or further mechanical failure while attempting to access the drive.
Freezers are readily available
For the average person trying to salvage data from a failed hard drive, putting the drive in a freezer is often more accessible than other methods of cooling it down. Methods like immersing the drive in liquid nitrogen or installing heat pumps require specialized equipment not readily available to most people. But freezers are ubiquitous in most homes and offices.
By simply sealing the hard drive in a plastic bag to protect it from moisture, it can be placed in a standard kitchen or laboratory freezer set to a very cold temperature. Most freezers can reach temperatures between -4°F (-20°C) and 0°F (-18°C) which is often cold enough to contract the internal hard drive components and realign the platters and heads.
It’s low cost
Using an already available freezer is also extremely low cost compared to other recovery methods which could require expensive equipment and professional data recovery services. For someone who just wants to attempt to salvage some personal photos, documents, or other data from a failed drive, the freezer trick is free or very low cost if a freezer needs to be purchased.
Even if unsuccessful, there is little risk or permanent damage to the drive from the cold temperatures. Once warmed back to room temperature, the drive can be sent for professional recovery if the freezer attempt did not work.
It can buy time to clone the drive
Even if freezing the hard drive does not fully repair it, it can sometimes buy enough time to clone or image the drive before it fails again. The temporarily contracted and realigned platters and heads may function well enough to mount the drive on a computer and make a complete sector by sector clone or image of the drive. This image can then be stored safely and examined in detail to extract files and data without risking further damage to the original drive.
Works best with minor mechanical failures
The freezer method works best with drives that have minor or early stage mechanical failures. If the drive failure is due to electronic component problems or severe mechanical damage, the freezing may not help realign the internal parts enough to recover data. But if the heads are slightly misaligned or platters warped due to heat or aging, cooling with a freezer has a decent chance of success.
Not a long term solution
It’s important to keep in mind that freezing a hard drive is only a short term solution. The effects only last as long as the drive stays cold. Once warmed up again, the mechanical components will warp and shift back out of alignment. So the freezing needs to be combined with immediately cloning or imaging the drive before the components revert back to their failed positions.
The freezer trick buys a short window of time to copy the data before the drive ultimately fails again. The drive will need to be kept frozen in order to maintain function and retrieving the data often requires repeating the process of freezing and thawing the drive to temporarily realign components.
Condensation is a risk
When cooling a hard drive in a freezer, condensation build up is a risk. Going from room temperature to below freezing will cause moisture in the air to condense on the hard drive platters once removed from the freezer. This liquid water can damage the platter surfaces or electronics. Steps must be taken to protect the drive from condensation.
A common technique is to place the hard drive in an airtight plastic bag before freezing. The bag should have as much air removed as possible. This prevents moisture from contacting the drive when it is taken out of the freezer. Allowing it to slowly warm to room temperature inside the bag reduces condensation issues.
Silica gel desiccant packs can also be put in the bag to absorb any residual moisture during the warming process. Once up to room temperature, the drive can be removed from the bag and immediately attached to a computer for data access before the components shift positions again.
Not effective for SSDs
While the freezer trick can potentially work for traditional hard disk drives, it is not applicable for SSDs (solid state drives). Because SSDs have no moving mechanical parts, cooling them does not realign components that have shifted position. Freezing an SSD will not help recover failed data.
Better options may exist
Freezing a failed hard drive should generally only be tried if no better options are available. While it can be low cost and accessible for some people, there are professional data recovery techniques that have a much higher chance of success. Companies with specialized clean room facilities can dismantle the drive and access the platters directly, imaging the data at a sector level. The costs range from a few hundred to a few thousand dollars.
If the data is truly valuable or critical, professional recovery is worth the cost compared to risking DIY solutions like freezing that have limited effectiveness and chances of total data loss if they damage the drive further.
Steps for freezing a hard drive
If you do decide to try freezing a failed hard drive to recover data, here are the basic steps to follow:
- Remove the hard drive from the computer or enclosure and place it in a sealable plastic bag.
- Force out as much air from the bag as possible before completely sealing it.
- Optional: Place silica gel desiccant packs in the bag to control moisture.
- Place the bagged hard drive in a freezer set between -4°F (-20°C) and 0°F (-18°C).
- Leave the drive in the freezer for at least 2 hours to cool down to freezing temperatures throughout.
- Remove the drive from the freezer, but keep it sealed in the bag until warmed to room temperature.
- Once at room temperature, remove the drive from the bag and immediately attach it to a computer system.
- Attempt to mount the drive and clone/image the data before the components fail again.
- Work quickly before the drive warms up and mechanical issues resurface.
Liquid nitrogen as an alternative
For even colder temperatures, liquid nitrogen baths can be used instead of freezers. Liquid nitrogen reaches temperatures as low as -320°F (-196°C) which significantly contracts the hard drive components for better realignment.
However, precautions must be taken to avoid condensing atmospheric moisture freezing on the drive. Vacuum sealing the drive or filling the container with pure nitrogen gas eliminates this risk. Liquid nitrogen also requires specialized equipment not readily available to most end users.
Conclusion
Freezing a hard drive is one method that may potentially recover data from mechanically failed drives before total failure occurs. While far from reliable, it can be low cost and accessible for some scenarios where professional recovery is not feasible. But better options like data recovery companies with specialized clean room facilities exist for more valuable data. At a minimum, freezing should allow enough time to clone or image the drive before it warms and fails again. With proper precautions against condensation, it provides a last resort option to try and salvage data from an otherwise dead drive.