  We study the proximity-induced superconducting correlations in a normal metal
connected to a superconductor when the interface between them is spin-active
and the normal metal is ballistic or diffusive. Remarkably, for any interface
spin polarization there is a critical interface resistance, above which the
conventional even-frequency proximity component vanishes completely at the
chemical potential, while the odd-frequency component remains finite. We
propose a way to unambiguously observe the odd-frequency component.
