Data Recovery Digest

In Windows, and most other operating systems, there are two basic formatting options: quick format and full format (sometimes referred to simply as a “format”). These two methods for reformatting your hard drive have slightly different results. But these differences may make or break your chances to recover data after a reformat. Read on to learn the important details.

Quick Format

Quick format is the same in Windows XP and later versions of Windows. A quick format prepares a drive that has already been formatted for use by creating a new file table on the drive. After a quick format, the drive will be treated as if it were blank, with nearly all of the free space available for new data. The reason a quick format is faster than a full format is because only the a small amount of meta information is deleted or overwritten. Any existing data on the drive is left virtually untouched.

Full Format

In Windows XP, a full format, or regular format, will create a new file table and scan the drive for bad sectors. This disk scan is what takes up the most time in a regular format in Windows XP. The disk check for bad sectors was part of the reason why Microsoft and other tech support professionals used to recommend a full format and reinstallation of Windows to fix certain PC issues. Note that the scan performed by Windows XP during a full format is similar to a ScanDisk operation.

In Windows Vista and later, a full format doesn’t include this check for bad sectors, except for the sectors where the file table is written. What it does do is write a new file table and erase all the existing data on the drive by overwriting it with zeros.

Data Recovery: Quick Format vs. Full Format

In the above scenarios, a quick format in Windows XP or later, or a full format in Windows XP or earlier will give you the best chances of data recovery. This is because the existing data is left untouched, meaning that a data recovery program could scan the disk (essentially ignoring the file table that says the disk is empty) and detect the old files. Your chances for recovering data from a quick formatted drive decreases as new data is written to it, since old data may be overwritten when new files are added to the volume.

For Windows Vista and later, a full format will prevent practically all consumer level data recovery utilities from recovering data that was written prior to the reformat. This is because all the old data has been overwritten during the format, rendering it irretrievable via software. Advanced data recovery labs can theoretically analyze the residual layers of magnetism to reconstruct previously written data, but this is very costly.

Conclusion

No one ever formats a disk with the intention of attempting a data recovery afterwards. But if you are deciding between a quick format and a full format on a regular basis, a quick format will usually suffice. It saves you time and, because Windows Vista and later mark bad sectors without a format, there isn’t a whole lot of performance benefit realized by performing a full format in Windows Vista and later. If you purposefully want to render data irrecoverable (for example, if you want to remove private photos or sensitive personal information from removable media or a hard disk drive), then go ahead and do a full format. This will decrease the chances of someone being able to recover the data afterwards.