Don't consider or proclaim a problem solved until you are sure that it is completely, permanently resolved, as more issues might crop up before then. A: "Acquiring this account will solve all our financial worries." B: "Hmm, don't whistle until you are out of the woods. If they pull out or can't pay us in time, we'll still be in trouble." A: "I'm confident that the treatment will eliminate the cancer very quickly." B: "Don't whistle until you're out of the woods, Doc. That cancer could still spread to other parts of the body."