How To Recover Lost Partition On External Hard Drive When a specific partition is deleted from a hard drive, all the files, documents, and folders will be completely wiped off. If you have lost your partition on your external hard drive and are looking for the procedure to recover the lost data, this page can help you do it in the best way possible. The most common reasons for losing a partition are disk formatting, bad sectors, accidental deletion, etc. But if the partition overlaps the existing partition, you cannot restore the one you have lost. Now, let us learn How To Recover Lost Partition On External Hard Drive.