diff --git a/usb_darwin.go b/usb_darwin.go
index 9b5c16c..fa63667 100644
--- a/usb_darwin.go
+++ b/usb_darwin.go
@@ -151,7 +151,17 @@ func (me *C.io_registry_entry_t) GetStringProperty(key string) (string, error) {
 		return "", errors.New("Property not found: " + key)
 	}
 	defer C.CFRelease(property)
-	return C.GoString(C.CFStringGetCStringPtr(property, 0)), nil
+
+	if ptr := C.CFStringGetCStringPtr(property, 0); ptr != nil {
+		return C.GoString(ptr), nil
+	}
+	// in certain circumstances CFStringGetCStringPtr may return NULL
+	// and we must retrieve the string by copy
+	buff := make([]C.char, 1024)
+	if C.CFStringGetCString(property, &buff[0], 1024, 0) != C.true {
+		return "", fmt.Errorf("Property '%s' can't be converted", key)
+	}
+	return C.GoString(&buff[0]), nil
 }
 
 func (me *C.io_registry_entry_t) GetIntProperty(key string, intType C.CFNumberType) (int, error) {
@@ -163,7 +173,9 @@ func (me *C.io_registry_entry_t) GetIntProperty(key string, intType C.CFNumberTy
 	}
 	defer C.CFRelease(property)
 	var res int
-	C.CFNumberGetValue(property, intType, unsafe.Pointer(&res))
+	if C.CFNumberGetValue(property, intType, unsafe.Pointer(&res)) != C.true {
+		return res, fmt.Errorf("Property '%s' can't be converted or has been truncated", key)
+	}
 	return res, nil
 }