The short answer is “No”, but we can certainly guarantee you can verify this with Disk Drill Basic at almost any moment. Each recovery case is unique, there’s absolutely no way to provide a universal recipe here. Well, I might be wrong. There IS a universal answer to that: we always recommend downloading Disk Drill Basic first (if you didn’t have it installed before the data loss), and running a scan with it to see if your files are still recoverable. Once you verify you can preview them, you are good to get the upgrade to Disk Drill PRO or Enterprise, if needed. And that preview is the guarantee you were looking for.
The longer answer requires an explanation of how computers store information and how data recovery works. Why is it that some files can be recovered, and others can’t? Even Disk Drill, using the most advanced data recovery methods, still comes up against the physical limitations of hard drive storage.
Disk Drill features several scan modes including Quick Scan and Deep Scan. You can learn more about all of them in this article. Quick Scan is good for files that have been accidentally deleted and other less severe cases. Most files are stored in fragments. Quick Scan follows the records in the file system to access the fragments that make up your file. Sometimes, however, the file system records are deleted. Imagine having the fragments of a file strewn around a hard drive, but not having any record of where these fragments are located. Your data is still present, but the hard drive has no idea of how to find it.
So why is a file stored in fragments, and why are these file fragments so scattered? As files are added to a hard drive over time, more and more space is taken up. Imagine that you have a completely full hard drive, but you then delete five different files, each of which takes up 100 MB. You now have 500 MB free. But the free space is not contiguous. When you now want to save a 200 MB file, there is no empty area that is large enough by itself. So your computer splits the 200 MB file in half and stores it in two of the 100 MB spaces. In real-world conditions, there is much more fragmentation!
Imagine having ten different jigsaw puzzles (each puzzle representing a file), and then mixing all of the pieces together. So when you apply a data recovery application such as Disk Drill, the application looks for the “addresses” in the file system that tells it how to put each puzzle together. If these addresses are found, Quick Scan can quickly produce results.
But file recovery is often not that easy. If the address information is gone for a deleted file (this happens more slowly on the FAT file system, but more quickly on NTFS and HFS/HFS+), there’s no way to know which fragments match each other. Another cause of problems is that individual areas on the hard drive can physically “go bad,” making their data inaccessible. So, in the case of that 200 MB file stored in two fragments, we would have a problem if one fragment was on a part of the hard drive that went bad: only half of the file would be readable.
Deep Scan is made for precisely such cases. Signature analysis allows Deep Scan to look for files based on their structure: Disk Drill knows how a file “should” look. Microsoft Word files have a different structure than Adobe Illustrator files, which have a different structure than iTunes music files, and so on. These structures give each kind of file a specific signature. With Deep Scan, Disk Drill goes through the accessible fragments, combining them in ways that make sense based on the signature of the file that you’re looking for. In good conditions, most or all of the fragments can be recovered. But sometimes, the file system does not even know where the fragments are: in these cases, unfortunately, there is no way to retrieve the information.
As a side note, large files have more fragments and require that more information about these fragments be stored in the file system, thus making more places where things can go wrong. This means that large files are less likely to be recovered completely and correctly, and are more likely to encounter corruption problems during recovery attempts.
As you can see, an awful lot in hard drive recovery depends on chance. And this is only the tip of the iceberg. You can read more about other Variables that Impact File Recovery Chances here. That’s why we strongly recommend keeping regular backups, which will take the risk out of keeping your data safe.
There are no guarantees of data recovery if you haven’t used Disk Drill’s data protection methods. As you can see from the explanation above, recovering a specific file is especially hard to predict. Recovering files is not a point-and-click affair, and what you want to find may not be the same as what you are able to find. With the limitations of storage technology, however, using Disk Drill and especially Deep Scan will give you the best chance possible of recovering your files.