I claim the ornamental design of a disposal installation support mount, as shown and described.
FIG. 1 is a perspective view taken from the top and front of a disposal installation support mount showing my new design, the broken line showing a disposal exterior portion is illustrative of environmental matter only for the support thereof and forming no part of the claimed design;
FIG. 2 is a top view of the disposal installation support mount;
FIG. 3 is a bottom view of the disposal installation support mount;
FIG. 4 is a front view of the disposal installation support mount;
FIG. 5 is a rear view of the disposal installation support mount; and,
FIG. 6 is a right side elevational view of the disposal installation support mount, the left side elevational view being the mirror image thereof.