Based on the fragment you provided ("Xf-autocad-kg X64-"), this refers to a specific type of file often associated with software licensing circumvention (a "keygen" for 64-bit AutoCAD).

How to Fix 'Your AutoCAD License Is Not Valid' [8 Solutions] - ZWSOFT

1. Purchase or subscribe via autodesk.com or an authorized reseller.
2. In your Autodesk Account → Products & Services → View Details → Product Key.
3. During installation, enter the serial number and product key.
4. Activate online or via manual request (no keygen required).

Using a keygen to activate software violates Autodesk’s Terms of Use. This is considered software piracy, which can lead to: