diff --git a/src/fs/io/FileOutputStream.cxx b/src/fs/io/FileOutputStream.cxx
index 082ca2fe8..0ee62a092 100644
--- a/src/fs/io/FileOutputStream.cxx
+++ b/src/fs/io/FileOutputStream.cxx
@@ -33,6 +33,12 @@
 
 FileOutputStream::FileOutputStream(Path _path, Mode _mode)
 	:path(_path), mode(_mode)
+{
+	Open();
+}
+
+inline void
+FileOutputStream::Open()
 {
 	switch (mode) {
 	case Mode::CREATE:
diff --git a/src/fs/io/FileOutputStream.hxx b/src/fs/io/FileOutputStream.hxx
index 1f6a34ccf..a17350adc 100644
--- a/src/fs/io/FileOutputStream.hxx
+++ b/src/fs/io/FileOutputStream.hxx
@@ -133,6 +133,7 @@ public:
 private:
 	void OpenCreate(bool visible);
 	void OpenAppend(bool create);
+	void Open();
 
 	bool Close() noexcept {
 		assert(IsDefined());