How to use Disk Drill Down for data recovery?

Are you trying to recover data from the internal boot drive or an external drive? This is very important.

To recover data from an external drive, you run the app and point it to the drive you need to recover data. Read the documentation for the software you are using since different versions of the software may behave differently.

To recover data from the internal boot drive, you must immediately stop using the drive as soon as you realize you need to recover data from it. You will need to boot from external media in order to run the data recovery software.

FYI, it is nearly impossible to recover any data from the internal SSD due to how SSDs work (especially if you already emptied the Trash, or used the command line to delete files).

If you are trying to recover data from an external Hard Drive, you will want to make sure the Hard Drive is healthy unless you accidentally deleted the data & emptied the Trash.

If the data disappeared due to a failing Hard Drive, then you may want to consider contacting a professional data recovery service since you usually only get one chance at recovering the data. The more you attempt to access a failing Hard Drive, the more likely the failure will get worse where even an expensive professional data recovery service will be unable to recover any data.

People should always have frequent and regular backups of their computer and all external media (including the cloud) which contains important & unique data. There are a lot more new ways to permanently lose access to the data stored on the internal SSD of the recent Macs due to all of the hardware, software, and security changes. Apple provides the Time Machine app with macOS to make backups easy, but there are also third party options as well which can be better suited for some system configurations.