The free version typically restricts you to recovering one file at a time or only low-resolution thumbnails. A valid key removes all limits, allowing you to batch-recover hundreds of files instantly.
Here is a useful guide regarding the DiskDigger key and license. disk digger key
This mode scans the filesystem (NTFS, FAT32, etc.) for records of deleted files that have not yet been overwritten. The free version typically restricts you to recovering