diff --git a/objectstore/BackendVFS.cpp b/objectstore/BackendVFS.cpp
index 39de51d984e2a500be2cda8e5d35e137c9b22ea3..2de741f09202fc1db7bb8d443322b861bedf8592 100644
--- a/objectstore/BackendVFS.cpp
+++ b/objectstore/BackendVFS.cpp
@@ -8,6 +8,7 @@
 #include <sys/file.h>
 #include <stdio.h>
 #include <memory>
+#include <unistd.h>