Hard Disk Sentinel Descriptive Essay

Hard disk case: Capacity is not correct

This example shows the status the status of a 3 TB hard disk, used with an older USB enclosure/adapter/docking station.

Hard disk problems reported

  • the hard disk drive seems accessible and working. File system on the logical drive (partition) is present, files seem available, showing no errors and the total space of the hard disk drive (3 TB in this case) seems usable

  • Hard Disk Sentinel shows a warning when it detects the hard disk drive:

  • Hard Disk Sentinel shows the text description:

    The detected total capacity (746 GB) of the drive Disk #5: WDC WD30EFRX ...
    is not correct, the capacity should be 2794 GB.

    Using the drive may cause file system corruption and/or data loss.
    It is recommended to check and modify the configuration or upgrade the operating system, hard disk controller and/or drivers to safely use this device.

Compatibility problem overview

Older hardware and/or operating systems/drivers may not be fully compatible with high capacity hard disks. Hard Disk Sentinel is the ONLY solution to be notified about such possible compatibility problems, without Hard Disk Sentinel the problem may remain completely undetectable until data loss.

Of course the problem is not related/caused by Hard Disk Sentinel and Hard Disk Sentinel can't fix the compatibility problem caused by some hardware/software elements, but can show this warning to indicate that there is a serious problem which require immediate attention.

Hard disk "capacity is not correct" problem may happen with any hard disk from any manufacturer over 2 TB and both under older Windows (XP / 2003) and newer Windows (7 / 8 / 10) systems as well.

Compatibility problem description

Older USB 2.0 and even some USB 3.0 adapters/enclosures/docking stations may not be fully compatible with hard disks over 2 TB in capacity.
When such combination of older USB adapters and high capacity hard disk drives used, the USB adapter may report smaller capacity than expected to the operating system as it does not use enough bits when detection and reporting the hard disk drive geometry and accessing data sectors.

Technically: older hard disk controllers/adapters/enclosures address the hard disk capacity and sectors in 32 bits only. It means they are able to address sectors up to 232-1, which is 4294967295 sectors. By 512 bytes/sector, it is 2199023255040 bytes, slightly more than 2 TB (2199023255040 / 1024 / 1024 / 1024).

So compatibility problem occurs when hard disks over that capacity (generally 3 TB and above) used.

More seriously, accessing sectors over the reported capacity does not generate any errors, this seems possible and working - but actually due to a sector address overflow, the beginning of the hard disk is accessed (read/written) again - instead of the end of the data area.

The result is that when the user starts to fill the logical drive (partition) with data and reaches the point where the overflow occurs, then the first sectors of the hard disk will be overwritten, causing serious and unrecoverable data loss - as the original data sectors (including Master Boot Record/partition table, MFT, directory entries, files, etc.) are all overwritten.

The problem may remain undetected until a complete power cycle (of the enclosure and/or the whole computer) when the cache flushed. Then, after restart, the hard disk seems not initialised and the partition, files are lost - and even data recovery tools/companies can't help as the original data area is overwritten - clearing all previously stored information.

Hard Disk Sentinel detects possible compatibility problems between these older devices (like controllers/enclosures/adapters/docking stations) and hard disks and immediately report the problem to increase attention.

As this problem is not really related to the hard disk, the hard disk drive Health and Performance % values are unaffected - but the immediate alert and the text description should suggest to stop using the current configuration immediately and improve the situation by changing the configuration (for example replacing the USB adapter/enclosure).

Other possible situations when "Capacity is not correct" message displayed

In some cases, hard disk controllers and their drivers may also not handle high capacity hard disks properly: due to addressing limit of the hard disk sectors, they may also have similar problem. If this happens, it is recommended to update the driver of the current hard disk controller (displayed on the Information page in Hard Disk Sentinel with its current driver date and version) from the Driver Zone page, which designed exactly to offer the best useful drivers for various hard disk controllers/chipsets/motherboards (which may not be the latest one in many cases).

Also under older Windows systems (like Windows XP) the previously mentioned compatibility issue may occur (even if the USB adapter is perfect and compatible with the high capacity hard disk in other, newer systems) and then Hard Disk Sentinel also shows the warning - and this is the reason of the It is recommended to check and modify the configuration or upgrade the operating system, hard disk controller and/or drivers to safely use this device section.

Verification of the problem

By default, there are no other indication of problem found, except that Hard Disk Sentinel displays the warning. But it is possible to verify the situation this way:

After right click on Computer, select Manage -> Disk Management option and then select the appropriate hard disk, it is possible to verify that Windows detected the total capacity of the hard disk as 746 GB:

Even worse, that it may show that (if the hard disk partitioned and formatted in an other system) the 746 GB hard disk contains the partition of the total capacity of the hard disk (2794 GB in this situation) - which does not seem correct.

Note that 1 GB = 1024 x 1024 x 1024 bytes.

And other way to "verify" the problem is by filling the logical drive (partition) completely: after high amount of data (2048 GB data is surely enough, in some cases even less are enough) copied to the hard disk, the partition and all previously saved files/folders will be lost. DO NOT attempt this if you have important data on the appropriate hard disk!


  • Always use Hard Disk Sentinel to be notified about possible issues, which may be related not only to hard disk problems / failures, but also about compatibility problems with older hard disk controller / driver / enclosure / adapter / docking station and the new high capacity hard disk drive.

  • Always observe the warning message and the text description in Hard Disk Sentinel, especially when a high capacity (over 2 TB) new external hard disk drive just connected, especially if you prefer to use the external hard disk drive with more computers.

  • Pay attention about such capacity-related warnings especially if you prefer to use an older USB adapter/enclosure/docking station with a newly purchased high capacity hard disk drive

  • Verify the situation especially if you use older operating system (Windows XP / 2003 or earlier) on one of your computers where you prefer to use the high capacity hard disk drive(s) otherwise writing to the hard disk by one of such computers may cause loss of data

  • If you receive such warning for an internal hard disk, then change/update driver of the hard disk controller (motherboard) where the hard disk drive connected from the Driver Zone page to ensure that the controller will address the total capacity correctly.

  • For higher compatibility with older operating systems and hardware, consider using hard disks with smaller capacities (up to 2 TB) if you prefer to use with Windows XP and/or older USB 2.0 enclosures/adapters


Re: Complete surface analysis vs. Surface scan

by hdsentinel » 2016.10.26. 08:46

Generally the trial versions show the complete description of each tests when you open the Disk menu -> Surface test window.

Read test - which means complete surface analysis:

Reads the disk surface to verify if all sectors are accessible and readable.
The test is safe, it does not affect stored data.
Disk problems may remain hidden and revealed disk issues are NOT fixed (like with ScanDisk).
The test measures transfer time for all blocks to reveal which areas of the surface are slower. As the block is slower, the associated color is darker.

Read + write + read test (refresh stored data)

Reads stored data from each blocks, writes back the contents and finally reads the information and compare with original contents. By the extensive test, an additional write cycle is used before writing back the contents to improve the efficiency of the error correction (drive regeneration).
The operation is usually safe for the stored information but data loss may occur if the system is not stable and/or upon power failure, overclocking, memory/power supply/cable problems and other factors.
The test can be used to refresh the data area of the storage device, without the need of complete erase but it is still recommended to backup important data before this test.
The test measures transfer time for all blocks to reveal which areas of the surface are slower. As the block is slower, the associated color is darker.

Reinitialise disk surface

Overwrites the disk surface with special initialization pattern to restore the sectors to default (empty) status and reads back sector contents, to verify if they are accessible and consistent. Forces the analysis of any weak sectors and verifies any hidden problems and fixes them by reallocation of bad sectors (this is drive regeneration).
Enables better use of the disk as after the test the spare area will be used instead of any problematic sectors.
Very intensive and time-consuming test, especially if the level (the number of overwrite cycles) is set to higher value.
The simple version of this test is usually (incorrectly) called as low level format by other tools.
The test measures transfer time for all blocks to reveal which areas of the surface are slower. As the block is slower, the associated color is darker.

Also there are other, hardware tests (Disk menu -> Short self test, Extended self test) functions are available. These can be started manually in both versions - and automatically / scheduled with the Pro version to perform regular testing to reveal problems.

Personally I'd more recommend the Pro version due to the higher testing / repairing functions. Also the Pro will have a new test soon, designed to easily and safely repair hard disk problems.

For more details about the tests, please check the Help -> Hard Disk Tests section in the software or on-line at:


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