diff --git a/cmd/common.go b/cmd/common.go
index 8f86fba..8237cb1 100644
--- a/cmd/common.go
+++ b/cmd/common.go
@@ -16,6 +16,7 @@ import (
 	"log"
 	"os"
 	"os/user"
+	"os/signal"
 	"path/filepath"
 	"sync"
 
@@ -330,6 +331,16 @@ func Main(statePath string, processCallback certspotter.ProcessCallback) int {
 		return 1
 	}
 
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt)
+	go func() {
+		<-c
+		if err := state.Unlock(); err != nil {
+			fmt.Fprintf(os.Stderr, "%s: Error unlocking state directory: %s\n", os.Args[0], err)
+		}
+		os.Exit(1)
+	}()
+
 	exitCode := 0
 	for i := range logs {
 		exitCode |= processLog(&logs[i], processCallback)