This is a general overview of the variables that can make your data more or less likely to be recoverable with Disk Drill. This list is by no means definitive.
Sometimes, even in the best situation, the data is lost. And sometimes, even under the worst conditions, the data can be found. There are cases when you can easily find smaller files from 4 years ago, and at the same time can’t find a 100MB document you deleted yesterday. This list is just for the purpose of giving you a general idea. Remember, luck is the necessary final ingredient.
The basics are this: Even after a file is deleted or dragged to the Trash, it usually still exists on the disk for some time until it is overwritten by new data. The computer marks the space that your deleted file took up as “empty” and thus available for new data to be saved there. But it often takes a long time before that space is actually filled. This is where Disk Drill comes in — it finds those files still lurking in the “empty” spaces. (Read Can You Guarantee That I Can Recover a Specific File? for a more detailed explanation of how file recovery works).
There are, of course, exceptions. Anytime you make a choice that “zeros out” a part of a disk after something is deleted, it becomes unrecoverable. The system literally writes zeros over the space where your data was, so the data is truly gone. See examples of this below in the “no recovery” section. In addition, if your disk is failing or has bad sectors, this also could cause permanent data loss, as Disk Drill may not be able to read those parts of the drive.
So, two rules of thumb for data recovery:
- Stop using your disk the moment you realize data has been lost and
- Don’t ever choose a “zero out” option unless you are really sure that you’ll never need to recover that data.
Variables That Increase Chances of Recovery:
- You just lost or deleted the files within the last few hours.
- You have not used the hard drive, memory card or other storage device since the data loss happened. (Meaning you have shut down your computer, or unplugged/shut down your external device).
- Your disk is healthy and there are no signs of it failing.
- You had plenty of available space (over 20%) on your hard drive when the data was lost.
- The files you need to recover are small in file size (under 50 MB).
- You follow the advice of our step-by-step Recovery tutorials, especially if you are recovering files on a Mac internal hard drive.
Variables That Decrease Chances of Recovery:
- Your files were lost or deleted a long time ago.
- You have saved new files to the disk, or (in the case of a hard drive) kept actively using it, since the data loss occurred.
- Your disk is full and you constantly delete old files to make room for new ones.
- Your disk is showing signs of corruption or failure.
- The files you need to recover are large in file size, such as videos.
- You are trying to recover a photo that was deleted using your camera’s interface (some cameras “zero out” data when a file is deleted).
- You do not follow the advice of our step-by-step tutorials, especially when it comes to recovering files on a Mac internal hard drive.
Variables that Indicate No Chance of Recovery:
- You used “secure empty trash” when deleting the file your want to recover.
- You have an SSD (solid state drive) with TRIM enabled.
- You used FileVault or any other encryption/compression software on the disk and don’t have the decryption keys. Though, FileVault will NOT affect your recovery success if the drive is decrypted and mounted properly.
- You selected an option to “zero out” a disk or partition when you formatted it.
- You defragmented the disk.
- You used third-party data-shredding software on the disk.
- Your disk or device where your lost data is stored cannot be mounted on Mac OS and it does not show up as an available volume in Disk Drill.