diff --git a/src/mu-store.cc b/src/mu-store.cc
index 5f7766a3..587958f4 100644
--- a/src/mu-store.cc
+++ b/src/mu-store.cc
@@ -26,6 +26,7 @@
 #include <xapian.h>
 #include <cstring>
 #include <stdexcept>
+#include <unistd.h>
 
 #include <errno.h>