For many years it’s been common knowledge among the more technically savvy computer enthusiasts, that even if you format your hard drive, the data can be recovered. Any simple data recovery software program and even most computer stores with a service department should be able to quickly restore your hard disk drive data after a format. And while this rule has been true for many years, there’s now a new sheriff in town, and he plays by different rules. With the advent of Vista and Windows 7, formatting your disc drive may now permanently destroy your computer data. Read on for the details …

In Windows, there are two types of formats that can be implemented; a quick format and a regular format. In the picture below, a quick format is selected, while un-checking the box would perform a regular format.

On older versions of Windows, up to and including Windows XP, a quick format overwrites the beginning of the MFT or Master File Table. The MFT is an index of all the files stored on a volume. Formatting re-initializes the MFT to appear to contain no data files by truncating the length of the known MFT. However, the orphaned index entries from before the quick format are still intact and can be used to recover all the previously existing files. With older versions of Windows, a regular format does exactly the same but it also tests for bad sectors across the entire drive. This test is non-destructive and does not overwrite any other data areas, so again all data files should be recoverable.

On newer versions of Windows, from Vista on and including Windows 7 and 8, a quick format does the same as with older versions and the data should be recoverable. BUT the regular format has changed substantially. It now overwrites “every” sector on the hard drive and as a result no data will be recoverable once this command is executed.

So why would Microsoft change the regular format to now erase every trace of data? Personally I believe it is in response to the increased awareness over data security and in particular the news coverage of personal data being discovered on tossed computers (see this interesting story on one couples adventure with leftover data files). Now, with just a simple regular format, Microsoft allows an end user to effectively do a complete and secure erase of all your hard drive’s personal content.

With new power comes new responsiblity, so be sure you know what you’re doing before formatting any hard disk drive, because even your friends at Memofix Data Recovery Services may not be able to help you.