diff --git a/src/cressi_edy.c b/src/cressi_edy.c
index d5c5482..1de3b53 100644
--- a/src/cressi_edy.c
+++ b/src/cressi_edy.c
@@ -188,6 +188,7 @@ cressi_edy_device_open (dc_device_t **out, dc_context_t *context, const char *na
 	// Set the default values.
 	device->port = NULL;
 	device->model = 0;
+	memset (device->fingerprint, 0, sizeof (device->fingerprint));
 
 	// Open the device.
 	int rc = serial_open (&device->port, context, name);
diff --git a/src/cressi_leonardo.c b/src/cressi_leonardo.c
index 87a6412..b2df764 100644
--- a/src/cressi_leonardo.c
+++ b/src/cressi_leonardo.c
@@ -89,6 +89,7 @@ cressi_leonardo_device_open (dc_device_t **out, dc_context_t *context, const cha
 
 	// Set the default values.
 	device->port = NULL;
+	memset (device->fingerprint, 0, sizeof (device->fingerprint));
 
 	// Open the device.
 	int rc = serial_open (&device->port, context, name);
diff --git a/src/diverite_nitekq.c b/src/diverite_nitekq.c
index 30692c6..e032fb6 100644
--- a/src/diverite_nitekq.c
+++ b/src/diverite_nitekq.c
@@ -164,6 +164,7 @@ diverite_nitekq_device_open (dc_device_t **out, dc_context_t *context, const cha
 
 	// Set the default values.
 	device->port = NULL;
+	memset (device->fingerprint, 0, sizeof (device->fingerprint));
 
 	// Open the device.
 	int rc = serial_open (&device->port, context, name);
diff --git a/src/zeagle_n2ition3.c b/src/zeagle_n2ition3.c
index 16b42f5..5c077d4 100644
--- a/src/zeagle_n2ition3.c
+++ b/src/zeagle_n2ition3.c
@@ -152,6 +152,7 @@ zeagle_n2ition3_device_open (dc_device_t **out, dc_context_t *context, const cha
 
 	// Set the default values.
 	device->port = NULL;
+	memset (device->fingerprint, 0, sizeof (device->fingerprint));
 
 	// Open the device.
 	int rc = serial_open (&device->port, context, name);