File & Data Recovery FAQ

Frequently asked questions about file recovery software

If the number of questions we get about file recovery are any gauge of an article's popularity, then our free file recovery software list must be one of the more popular pieces on our site.

In other words, the complicated and often misunderstood topic of recovering deleted files rightly generates a lot of confusion.

Beyond that, to both shrink our ever-growing inbox and to settle the minds of those that decide not to take the time to ask a question, here are answers to some of the more common questions we get regarding these "undelete" programs and file recovery in general.

A dismantled hard drive.
 

Can I undelete a file if I don't have a file recovery tool?

Yes. Not having a data recovery program already installed doesn't preclude you from being able to recover a file. In other words, if you've deleted a file you want back, go download a data recovery program, and run it.

Having a file recovery program installed doesn't mean that it's watching for deleted files or storing backup versions of files for you to restore in the future. Instead, data recovery tools scan your hard drive or other storage device for previously deleted files which, surprising to many, aren't really gone, just hidden from the operating system.

Assuming that physical space hasn't already been overwritten, you'll probably have no problem undeleting the file.

Unless you mean quite literally that you just deleted a file? If so, check the Recycle Bin. The file you want to recover is probably sitting in there.

See How to Restore Deleted Files From the Recycle Bin if you've never gotten a file back out of the Recycle Bin before.

Will a data recovery program undelete anything ever deleted?

The short answer is no, a data recovery program will not "undelete" anything, but it's a bit more complicated than that.

While this might surprise you to learn, the information in a file, for example, doesn't actually get removed when it's deleted. The ​file system, which is like an index that keeps track of where the pieces of a file are located, simply marks the areas that contained the file as free space that the operating system can overwrite with new data.

In other words, the map coordinates that held the location of the file is removed from the index, essentially making the file invisible to the operating system... and to you. Of course, invisible is very different than gone forever, which is great news.

A file recovery program works by exploiting the fact that, while the directions to a file are missing, the actual file is not, so long as that physical space has not been overwritten by something new already.

So now that you know a bit more about how it works, we can better answer the question: a file recovery program is not likely to undelete everything you've ever deleted because at least some of the physical space occupied by those deleted files has likely been overwritten with new files.

How long is too long before a file is unrecoverable?

It depends, but generally, the sooner you try to recover the file after deleting it, the more likely it'll be recoverable.

If the file you want back was deleted recently, it's much more likely to be undeletable than a file that was removed days or weeks ago, and especially something deleted longer than that.

The reason this works at all is because when you delete a file, you don't really remove the data, only the directions to it. The space occupied by that data is marked as free and will eventually be overwritten.

The key, then, is to minimize the writing of data to the drive that contains the deleted file. In other words, the less writing activity (saving files, installing software, etc.) on the drive, the longer, in general, the deleted files on that drive will be able to be recovered.

For example, if you delete a saved video and then promptly turn off your computer and leave it off for three years, you could theoretically turn the computer back on, run a file recovery program, and completely restore that file. This is because very little data has had a chance to have been written to the drive, potentially overwriting the video.

In a more realistic example, let's say you delete a saved video. For weeks, or even just days, you use your computer normally, downloading more videos, editing some photos, etc. Depending on things like how big the drive you're working from is, the amount of data you're writing to the drive, and the size of the deleted video, chances are it won't be recoverable.

In general, the larger a file is, the shorter time frame you have to undelete it. This is because the parts of a larger file are spread over a larger swath of your physical drive, increasing the likelihood of part of the file being overwritten.

Can I recover files from SD cards, flash drives, etc.?

Absolutely yes! A number of data recovery tools, especially the higher-ranking ones in our list, support a wide range of devices like SD cards, external hard drives, flash drives, and other USB based drives.

In addition to your classic internal hard drive, you'll find on most desktop, laptop, and tablet computers, most data recovery tools also support SD cards, external hard drives, flash drives, and some even support iPhones, iPads, and other ultraportable computer devices that store files.

A few data recovery tools even support undeleting files from rewritable optical drive media, like CD, DVD, and BD discs.

Most file recovery programs support any device that you can plug into your computer and display the contents of as a drive. This is pretty common with things like digital cameras, smartphones, etc.

Technically, whether a program supports one storage device over another depends on the file system that the particular file recovery program supports. In other words, it's not the device itself that needs to be supported, but instead the way in which the device stores data.

Do file recovery tools support network drives?

This is tricky because all network drives work a little differently. The short answer is that yes, you can, but you have to go directly to that drive to trigger the recovery process.

Shared Drives

Data recovery tools can't recover deleted files from a shared drive.

The reasons they don't work are complicated but have to do with the fact that the program doesn't have the level of access to the physical hard drive that it needs to do its job, even though the shared network resource may otherwise look and act like any other drive on your computer.

Your computer's operating system doesn't control the shared drive. Some other computer's OS does. If you have access to the computer where the shared drive is located, go there and try to undelete the file with a file recovery program.

Network Drives

Network storage devices that connect directly to your network and don't need a computer aren't as easy to find a workaround for. There's an operating system supporting the drive, and any file recovery has to be initiated from within that drive.

If you want to recover a deleted file from a network storage device, log on to the web-based administration for the device and see if any integrated file recovery features that might be helpful exist.

As a last resort, try connecting the hard drive inside the network storage device directly to your computer. If you're successful, you can then run data recovery software against it from there.

Cloud Storage

Data recovery tools you have installed on your computer are of no use when online storage services are involved. If you need to recover a file you deleted from a cloud service, log in and see if there's a trash can or recycle bin that may be storing the file. There almost always is.

Should I install the data recovery program or use the portable version?

Choose the portable option if you've already deleted the file. Installing the software is fine to do if you're just preparing your computer for a possible file recovery in the future.

The most important thing to know is that both versions of the tool do exactly the same thing. In other words, they're identical programs, aside from a very important difference:

The installable version installs to your hard drive, placing files all over your computer in the process—like most programs you download or purchase do.

The portable version does not install to your hard drive, but instead runs self-contained in the folder that you extracted the downloaded file's contents to.

In general, we like portable, self-contained programs. They don't leave shortcuts, DLL files, and registry keys all over your computer. They also don't need to be uninstalled, just deleted from where they stand. It's an overall "cleaner" experience, in our opinion, to use portable software when you can.

Now, multiply our preference for portable software in general 1,000,000 times and that comes close to how much we prefer portable file recovery programs over installable ones, and here's why:

The single most important thing you can do to make sure a file you've deleted will be recoverable is to stop writing information to the drive that had that file on it.

Installing software is one of the most write-heavy things you could possibly do, so "installing" a file recovery program is a very ironic, and potentially destructive, thing to do.

In a perfect scenario, which may or may not be possible for you, you'll choose the portable version of a free file recovery program, download it to another drive, like a flash drive or second hard drive, and run it directly from there.

Where you run a data recovery tool from doesn't impact where you search for deleted files on, so don't worry about that.

A related concern we've heard is whether the data recovery file scanning process itself writes data to the drive, potentially impacting any future recovery if the program in use doesn't pan out. The answer to that, luckily, is no. Feel free to scan with as many tools as you want—just remember to use the portable version!

Why are some deleted files not 100% recoverable?

The whole file has to be available for it to be fully recoverable, but depending on its size and the time that's elapsed since the deletion, parts of the file might have already been overwritten by other data.

When your computer writes data to your hard drive, or some other storage media, it's not necessarily written to the drive in a perfect order. Divisible pieces of the file are written to parts of the media that may not sit next to each other physically. This is called fragmentation.

Even files we might consider to be small contain many thousands of divisible pieces. For example, a music file could in reality be heavily fragmented, spread all over the drive it's stored on.

Your computer sees the area occupied by a deleted file as free space, allowing other data to be written there. So, for example, if the area occupied by 10% of your MP3 file has been overwritten by part of a program you installed or a new video you downloaded, then only 90% of the data that made up your deleted MP3 file still exists.

That was a simplistic example, but hopefully that helped you understand why certain percentages of some files still exist.

To the question of the usability of just part of a file: it depends on what kind of file we're talking about and also what parts of the file are missing, the latter of which you can't be sure of.

So, unfortunately, in most cases, no, restoring a file that has missing data will usually result in a worthless file.

Can I recover files from a failed hard drive?

If failed is to mean a physical problem with the hard drive, then no, a file recovery program isn't likely to help. Since software needs access to your hard drive like any other program, it's only valuable if the hard drive is in otherwise working order.

Physical damage to a hard drive, or other storage device, doesn't mean all hope is lost, it just means that a file recovery tool isn't your next step. Your best solution to recover data from a damaged hard drive is to employ the services of a data recovery service. These services have the specialized hardware, expertise, and lab environments necessary to help repair and restore the data from damaged hard drives.

However, if you're experiencing a BSOD or some other major error or situation that's just preventing Windows from starting properly, that doesn't necessarily mean that your hard drive has a physical or unrecoverable problem.

In fact, just because your computer won't start, doesn't at all mean your files are gone—it just means that you can't access them right now.

What you need to do is get your computer started again. See How to Fix a Computer That Won't Turn On for help doing that.

If that doesn't work, connecting the hard drive with your important data on it to another computer, either directly or via a USB hard drive enclosure, is your next best solution.

Beyond those questions and answers, If you haven't yet, be sure to read through our complete tutorial on this topic, How to Recover Deleted Files. It will probably clear up any lingering questions.