We argue that in a fluid, or magnet, confined by adsorbing walls which favo
r liquid, or the (+) phase, the solvation (Casimir) force in the vicinity o
f the critical point is strongly influenced by capillary condensation which
occurs below the bulk critical temperature T-c. At T slightly below and ab
ove T-c, a small bulk field h < 0, which favors gas, or the (-) phase, lead
s to residual condensation and a solvation force which is much more attract
ive (at the same large wall separation) than that found exactly at the crit
ical point. Our predictions are supported by results obtained from density-
matrix renormalization-group calculations in a two-dimensional Ising strip
subject to identical surface fields.