Encrypting File System (EFS) works on individual files or folders, rather than at the whole disk level like BitLocker does. EFS shows up in the business editions of Windows (like Pro, Professional, Business, Ultimate, Enterprise and Education) The encryption/decryption is carried out in the NTFS driver. The EFS ransomware was tested with Windows 10 64-bit versions 1803, 1809 and 1903, but should also work on Windows 32-bit operating systems.”]
Source: https://www.darkreading.com/abtv/efs-ransomware-slips-by-av-products/a/d-id/757014