No matter how easy the process of backing up data is, and how many times the importance of keeping good backups is stressed, we have all suffered the experience of lost data. Sometimes it is down to something as simple as careless deletion or reformatting, other times it comes alongside that sinking feeling that a drive has died for good.
Getting lost data back can range from being a relatively quick and easy procedure, all the way through to costing more than your PC itself, as professionals carefully dismantle the drive and use fancy techniques to access what remains on the platters. Given that a hard disk is a complex mechanical beast, if it is physically damaged you’ll end up resorting to the latter, or making peace with the fact that your data is gone for good.
If your hard drive is physically fine though, there are several things you can do to try and get your data back through software. However, this can also be a costly procedure, involving the purchase of a custom suite designed to dig through your hard disk and recover fragments of lost files. As you’ll likely be aware, when one deletes a file from a PC, it doesn’t actually get removed from the disk – instead, the reference to its location is forgotten by your file system. Even if you reformat a drive, a similar process occurs, and your data will sit, invisible, until it is written over by new information.
This doesn’t apply to SSDs, due to the use of technologies like TRIM and Garbage Collection. These are used to stop the performance of an SSD degrading over time due to the nature of Flash Memory. When you erase the reference to a file on an SSD the data is still there, like a hard disk. However when you go to write new data to that section, the flash memory first has to be erased, and then written over. This process slows down the SSD, which led to the creation of the TRIM command. This is sent to the SSD by a supported operating system during idle times, and tells the drive to go ahead and erase the data from the flash memory marked as empty. While this has been crucial to the viability of the SSD as a storage device, it makes recovering data that much trickier.
It is important to note that, while this applies to SSDs, it doesn’t apply to other flash storage devices like USB sticks and SD cards. That means these are similar to hard disks when it comes to recovering data, and accidental deletion or formatting can be undone.
The easy, and free, first step in data recovery
A recent reformatting-without-thinking episode had us searching around for suitable undelete tools online, and stumbling through a minefield of ‘free’ software that would find files and show us their existence, then instruct us to buy a full version to recover them. Other tools would let us grab files under 1MB, but have to commit to a full version to let us get our hands on bigger ones.
Given that such an incident will never happen again because of certain lessons learned about regular backups, we didn’t want to drop a chunk of cash on software. Thankfully there are a few free options that are a good first port of call to see if you can get your data back before buying one of the more featured software packages.
The two we found most useful are Photorec and Recuva. Photorec is an open source offering that started life as a tool to grab lost images from SD cards, and has evolved to work with a wide array of filetypes. The downside for some is that it uses a text-based interface, which can be a bit daunting for most users, and you’ll want a degree of knowledge about your file systems to make it work.