In the majority of logical failure cases, the drive still spins, is recognized by the BIOS, but will not boot. Recovering data from a hard disk drive with the logical failure does not require the drive repair. In this case all components of the hard drive are physically undamaged and the drive is considered as fully functional. But the data is unreadable and the operating system is not able to access some or all files, partitions, or folders.
The most common causes of Logical Hard Drive Failures:
- Critical file system’s objects are inaccessible (erased or overwritten partially or completely for any reason). The examples of such objects are Master Boot Record (also known as Partition Table), Boot Sector, Master File Table for NTFS file system (Windows) or Catalog File for HFS file system (Apple). As a result, computer’s operating system is not able to work with the drive correctly: it will not boot if the drive is supposed to be bootable or it will show it as an unreadable volume if the affected drive is connected via secondary ATA port or USB connection. The reasons for critical file system’s objects being inaccessible are usually power surges, improper shutdown, computer virus, human error.
- Operating system errors or registry damage can also be a cause of logical hard drive failures. They may result from virus attacks and malware contaminated applications.
- Deleted files. Usually the reason for this type of logical failure is a human error. Keep in mind that if a file was Deleted or even Shift-Deleted (removed from Recycle Bin) there are very good chances for successful data recovery unless it’s being overwritten with newer data This is how it works: when a file is deleted in NTFS file system , it is only marked as deleted within the MFT (Master File Table) entry for that file, while clusters that were allocated to this file are marked as free within the Bitmap (cluster allocation table). This means the file is still there but it can be easily overwritten! Once you discover that you’ve accidentally deleted your important files – shut down the computer, avoid using it by all means and send your drive to data recovery professionals.
- Accidentally repartitioned or reformatted drive. Again, the reason for this failure is a human error. Luckily, data recovery from repartitioned or reformatted drives will be 100% successful unless your hard drive is full-formatted (zero-filled) other than quick-formatted (new empty Master File Table created, old one stays practically intact).
- Overwritten data. This is a tough one to handle. Usually happens when people are using “restore my computer to factory settings” without realizing that this procedure actually overwrites their old data (precious family photos, crucial business documents, irreplaceable emails etc.) with large amount of newer one (tons of stupid useless bloatware bundled by their computer’s manufacturer). Recovery is still possible! – with the help of sophisticated data recovery software tools we are able to deep-scan the affected drive and reconstruct the majority of data from bits and pieces.