diff --git a/main.c b/main.c
index eee5415..cb6f6dc 100644
--- a/main.c
+++ b/main.c
@@ -6,7 +6,7 @@
 #include "mmpriv.h"
 #include "ketopt.h"
 
-#define MM_VERSION "2.13-r881-dirty"
+#define MM_VERSION "2.13-r882-dirty"
 
 #ifdef __linux__
 #include <sys/resource.h>
diff --git a/options.c b/options.c
index c7f0eeb..b6d9004 100644
--- a/options.c
+++ b/options.c
@@ -159,6 +159,11 @@ int mm_check_opt(const mm_idxopt_t *io, const mm_mapopt_t *mo)
 			fprintf(stderr, "[ERROR]\033[1;31m --for-only and --rev-only can't be applied at the same time\033[0m\n");
 		return -3;
 	}
+	if (mo->e <= 0 || mo->q <= 0) {
+		if (mm_verbose >= 1)
+			fprintf(stderr, "[ERROR]\033[1;31m -O and -E must be positive\033[0m\n");
+		return -1;
+	}
 	if ((mo->q != mo->q2 || mo->e != mo->e2) && !(mo->e > mo->e2 && mo->q + mo->e < mo->q2 + mo->e2)) {
 		if (mm_verbose >= 1)
 			fprintf(stderr, "[ERROR]\033[1;31m dual gap penalties violating E1>E2 and O1+E1<O2+E2\033[0m\n");