Hard Disk Validator

When you copy something on your hard drive, a checksum is also generated for each block unit, and it should always match the data stored in a certain sector. When this is not the case, you will end up with a bad sector, which is inaccessible and unusable.
Hard Disk Validator is an open-source utility that scans for these bad sectors and overwrites the stored data, thus allowing the sector to be used again. It is very simple to use and fully portable.

How bad sectors appear and how you can deal with them

Each block unit on your hard drive also stores a checksum that is used to verify the integrity of the data. If the checksum does not match the data, the sector will be seen as invalid and will no longer be accessible.
Bad sectors can have a number of causes, the most common being malfunctioning hard drives or power failures. It is always a good idea to check your HDD for bad sectors after an unexpected shutdown.

Scan your hard drive for bad sectors and repair them

Hard Disk Validator can run four different tests to help you locate and deal with bad sectors. It is important to choose the right one so as not to lose important data.
The first two tests are designed to scan your HDD for bad sectors, overwrite them if they are found and read the data to make sure it was written successfully.
The third test writes a test pattern on the disk, verifies if it was written successfully and then restores the original data. The fourth test skips the last part, which means the original data will be lost.

Easy-to-use, portable HDD checker

While it clearly does not offer any advanced features, Hard Disk Validator is an excellent tool for users who wish to quickly check their hard drives for bad sectors and repair them.
It is worth noting that this is a fully portable application, so it will not leave any traces behind and can even be run from portable storage devices.