The answer to 'stone walkway mud' is that a stone walkway can become muddy due to poor drainage, soil erosion, or settling of the underlying base. Symptoms may include standing water, soft or spongy areas, and a buildup of mud or silt on the surface. Solutions can include improving drainage, reinforcing the base, or resetting the stones.
For minor issues, homeowners may be able to DIY by clearing debris, adjusting the grading, or adding gravel or sand to the problem areas. However, more extensive repairs like regrading, installing drainage systems, or completely rebuilding the walkway are best left to professional landscapers who have the right equipment and expertise.