The .lnk file extension refers to a shortcut link on your computer, not the actual file. This occurs when you upload the document while the file is still open or if you load the file from the Recent Files folder instead of My Documents, My Computer, or the Desktop.
This problem make you uncomfortable to use your computer. So let's fix it now.
METHOD #11. Open the Registry Editor (click Windows + R, type regedit, hit enter).
2. Navigate to this registry branch:
3. Find the subkey called User Choice and delete it.
4. Close Registry Editor.
5. Reboot your PC.