What to Do When Getting the Reallocated Sector Count Warning

What Is Reallocated Sector Count?

The Reallocated Sector Count is a critical S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology) metric on hard drives and some SSDs. It tracks the number of bad, unreadable sectors the drive’s firmware has isolated and moved to a hidden, healthy reserve pool. 

Detailed Explanation:

Both HDDs and modern SSDs conceal a portion of their total physical capacity that is completely unaddressable by the host operating system. This portion of capacity is called spare sectors/blocks (SSD spare blocks are included in SSD Over Provisioning).

The spare sectors/blocks are used to automatically replace and take over data when the original sector is physically damaged. This process is recorded in the S.M.A.R.T. information of the hard drive, namely the Reallocated Sector Count.

Reallocated Sector Count Result Explanation

To check the Reallocated Sector Count on your drive, you need to use third-party software like CrystalDiskInfo, Hard Disk Sentinel, HDDScan, etc. These programs will read and display the S.M.A.R.T. information.

Then, how to understand the Reallocated Sector Count result? You need to view its Current, Worst, Threshold, and Raw Values.

• Current Value: A health score that typically starts at a high value (like 100 or 200) and decreases as your drive ages and sectors fail. Higher numbers are better.
• Worst Value: The lowest health score the drive has ever recorded during its entire lifespan.
• Threshold Value: A manufacturer-set limit. If your Current score drops to or below this threshold, the drive has failed its S.M.A.R.T. health test and is generally considered unusable.
• Raw Value: This is the most important number. It shows the actual physical count of sectors that have been reallocated. If the Raw Value is larger than 0, but the Current score is still high, the drive is compensating for damage. However, because sectors have started to fail, the drive is officially aging and may not remain reliable.

There are also some other S.M.A.R.T. related parameters.

• Current Pending Sector Count: The current count of unstable sectors on your disk that are waiting to be reallocated to spare drive space.
• Reallocation Event Count: A count of the attempts to transfer data from a bad sector to a special reserved area (spare area).
• Uncorrectable Sector Count: The total number of uncorrectable errors when reading/writing a sector.

How Many Reallocated Sector Count Is Bad?

Any number (raw value) greater than zero is a sign that a hard drive is degrading. If you value your data highly, you can back it up immediately and replace the disk.

If you can tolerate a sudden, outright drive failure, you can back up your data first and monitor the Reallocated Sector Count value. Then, replace the disk only when the value rises significantly.

For specific instructions, please refer to the table below.

Clone the Disk

The Reallocated Sector Count warning can’t be solved by any software tool, format, or utility. In most cases, all you need to do is clone the disk and then replace it.

To clone the disk, you can use MiniTool Partition Wizard. Here is the guide:

MiniTool Partition Wizard DemoClick to Download100%Clean & Safe

Step 1: Connect the target disk (where cloned content is put) to your PC. According to your PC condition, you can either install the target disk into your PC directly or connect it via a SATA/M.2 to USB adapter.

Step 2: Launch MiniTool Partition Wizard. Select the disk with the Reallocated Sector Count warning, and then choose Copy Disk from the left action panel.

Step 3: Select a target disk as the destination and click Next. A warning window will pop up telling you that all the data on the disk will be destroyed. Click Yes if you want to continue.

Step 4: Choose the copy options and adjust the target disk layout. You can keep the default settings here.

Step 5: Read the NOTE and click Finish. Then, click Apply to execute the pending operation.

In very rare cases, you may need to recover data from the disk with the Reallocated Sector Count warning. If so, MiniTool Partition Wizard can also help you. As for the guide, you can refer to this post: Recover Data from Hard Drives with Bad Sectors.

Reasons for Reallocated Sector Count Warning

The Reallocated Sector Count increases when a disk sector fails for the following reasons.

• Age and Wear: Over the years, the magnetic coating on HDD platters gradually weakens, and the flash memory chips in SSDs also wear down. This can lead to bad sectors or blocks, triggering the Reallocated Sector Count to rise.
• Heat Damage: The ideal operating temperature for HDDs is 40°C to 45°C, while the optimal operating temperature for SSDs is approximately 50°C to 55°C. If a hard drive operates in a high-heat environment for an extended period, it is highly susceptible to thermal damage, leading to bad sectors/blocks.
• Physical Shock: Hard drives can be physically damaged by being dropped, bumped while running, or even placed on surfaces that vibrate excessively, resulting in bad sectors/blocks.
• Power Issues: When a hard drive experiences a sudden power outage, voltage spike, or power instability during a write operation, the data being written to the sector may become corrupted or incomplete. Even if the sector itself is not physically damaged, the firmware may mark it as unreliable and reallocate it.
• Manufacturing Defects: Some hard drives come with barely acceptable sectors at the factory. These sectors pass initial quality tests but may fail in actual use. If you discover reassigned sectors within the first few weeks of a new hard drive, you can use the warranty.

To prevent data loss from hard drive failure, you can monitor S.M.A.R.T. regularly, keep drives cool, use a UPS (uninterruptible power supply), adopt the 3-2-1 backup strategy, and replace drives before they fail.

What does Reallocated Sector Count mean? How to understand its result? How many Reallocated Sector Count is bad? What causes the Reallocated Sector Count warning? How to deal with this warning? All the things are explained in this post.Click to Tweet

Bottom Line

If you encounter a Reallocated Sector Count SSD or HDD warning, remember to make an urgent backup. If you encounter issues when cloning the disk via MiniTool Partition Wizard, contact us via [email protected] for help.