diff --git a/bwtsw2_pair.c b/bwtsw2_pair.c
index cad96e9..cdd822f 100644
--- a/bwtsw2_pair.c
+++ b/bwtsw2_pair.c
@@ -46,7 +46,7 @@ bsw2pestat_t bsw2_stat(int n, bwtsw2_t **buf, kstring_t *msg, int max_ins)
 	p75 = isize[(int)(.75 * k + .499)];
 	ksprintf(msg, "[%s] infer the insert size distribution from %d high-quality pairs.\n", __func__, k);
 	if (k < 8) {
-		ksprintf(msg, "[%s] fail to infer the insert size distribution.\n", __func__);
+		ksprintf(msg, "[%s] fail to infer the insert size distribution: too few good pairs.\n", __func__);
 		free(isize);
 		r.failed = 1;
 		return r;
@@ -55,6 +55,12 @@ bsw2pestat_t bsw2_stat(int n, bwtsw2_t **buf, kstring_t *msg, int max_ins)
 	r.low  = tmp > max_len? tmp : max_len;
 	if (r.low < 1) r.low = 1;
 	r.high = (int)(p75 + OUTLIER_BOUND * (p75 - p25) + .499);
+	if (r.low > r.high) {
+		ksprintf(msg, "[%s] fail to infer the insert size distribution: upper bound is smaller than max read length.\n", __func__);
+		free(isize);
+		r.failed = 1;
+		return r;
+	}
 	ksprintf(msg, "[%s] (25, 50, 75) percentile: (%d, %d, %d)\n", __func__, p25, p50, p75);
 	ksprintf(msg, "[%s] low and high boundaries for computing mean and std.dev: (%d, %d)\n", __func__, r.low, r.high);
 	for (i = x = 0, r.avg = 0; i < k; ++i)
diff --git a/main.c b/main.c
index 85e41b2..aee4772 100644
--- a/main.c
+++ b/main.c
@@ -3,7 +3,7 @@
 #include "utils.h"
 
 #ifndef PACKAGE_VERSION
-#define PACKAGE_VERSION "0.7.3-r381-beta"
+#define PACKAGE_VERSION "0.7.3-r382-beta"
 #endif
 
 int bwa_fa2pac(int argc, char *argv[]);