Some customers send their hard drive for data recovery. When verifying data, they find that some files cannot be opened or the files are garbled. Some photos thumbnails are normal, but after opening, they find that the photos are bad. Or when the restored short film is playing, the picture is normal but there is no sound or sound asynchrony. Can data under these situations be restored?
Accurately speaking, these situations can generally be analyzed from two perspectives. First of all, these situations are related to the storage structure of data. When we store data into hard drive, all kinds of operating systems have their own unique storage modes. A file may be stored on hard drive continuously, or it may be divided into several parts and stored on hard drive separately. Several parts stored separately will clearly give the specific location of the next part. When we carry out data recovery, for some faults, as the hard drive damage is too serious, some parts of the hard drive data cannot be extracted. Therefore, several parts of the file cannot be re-combined. Thus, the file cannot be opened or the file is garbled. Secondly, because the directory location of hard drive is destroyed or can't be read, the directing of the file location is wrong, so that the underlying information of data that does not belong to this file is extracted. Hence, the file we open is not the original data at all, leading to the phenomenon that the file can't be opened or the file is garbled.
So, does this really mean that data can't be recovered? The answer, of course, is not. Engineers familiar with file systems can open files normally by analyzing the underlying information of hard drive data in detail, extracting each part of the file, recombining and repairing it. But if the missing of the file is very serious, it can't be repaired. Of course, this manual analysis technology of hard drive is very high-end and difficult with large workload. Hence, when a file cannot be opened or contains garbled texts, it does not mean that the file cannot be recovered.