diff --git a/src/util/memstream.c b/src/util/memstream.c
index f133a527341..8840228563a 100644
--- a/src/util/memstream.c
+++ b/src/util/memstream.c
@@ -30,7 +30,7 @@
 bool
 u_memstream_open(struct u_memstream *mem, char **bufp, size_t *sizep)
 {
-#ifdef _WIN32
+#if defined(_WIN32)
    bool success = false;
 
    char path[MAX_PATH];
@@ -51,6 +51,8 @@ u_memstream_open(struct u_memstream *mem, char **bufp, size_t *sizep)
    }
 
    return success;
+#elif defined(__APPLE__)
+   return false;
 #else
    FILE *const f = open_memstream(bufp, sizep);
    mem->f = f;