diff --git a/src/out.c b/src/out.c
index 868e711..c4c80d9 100644
--- a/src/out.c
+++ b/src/out.c
@@ -329,7 +329,7 @@
     LY_CHECK_ERR_RET(!*out, LOGMEM(NULL), LY_EMEM);
 
     (*out)->type = LY_OUT_FILEPATH;
-    (*out)->method.fpath.f = fopen(filepath, "w");
+    (*out)->method.fpath.f = fopen(filepath, "wb");
     if (!(*out)->method.fpath.f) {
         LOGERR(NULL, LY_ESYS, "Failed to open file \"%s\" (%s).", filepath, strerror(errno));
         free(*out);
@@ -353,7 +353,7 @@
 
     /* replace filepath */
     f = out->method.fpath.f;
-    out->method.fpath.f = fopen(filepath, "w");
+    out->method.fpath.f = fopen(filepath, "wb");
     if (!out->method.fpath.f) {
         LOGERR(NULL, LY_ESYS, "Failed to open file \"%s\" (%s).", filepath, strerror(errno));
         out->method.fpath.f = f;