The answer to 'why is my stone walkway' is that there are several common causes for issues with stone walkways, including settling, cracking, heaving, and staining. Symptoms may include uneven or cracked stones, loose or missing stones, and discoloration or staining.
Some common causes are improper installation, soil erosion, freeze-thaw cycles, and heavy foot traffic. Solutions can range from resetting or replacing individual stones to more extensive repairs like re-leveling the entire walkway. DIY repairs may be possible for minor issues, but more complex problems often require the expertise of a professional landscaper.