To use the full features of Recover My Files v5.2.1, such as saving recovered data, you must purchase a valid license key from the official developer, GetData. How to Get and Use a License Key
You have two legitimate ways to use Recover My Files v5.2.1 without paying full price: license key for recover my files v5.2.1
The official free trial lets you:
Do not download or install recovery tools onto the same drive you are trying to rescue. Save to a different disk. To use the full features of Recover My Files v5