diff --git a/NEWS b/NEWS
index 8560c1187..2cfd2c025 100644
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,6 @@
 ver 0.21.3 (not yet released)
+* output
+  - alsa: fix crash bug
 
 ver 0.21.2 (2018/11/12)
 * protocol
diff --git a/src/output/plugins/AlsaOutputPlugin.cxx b/src/output/plugins/AlsaOutputPlugin.cxx
index 8b505db7d..c72cf4ea2 100644
--- a/src/output/plugins/AlsaOutputPlugin.cxx
+++ b/src/output/plugins/AlsaOutputPlugin.cxx
@@ -306,6 +306,8 @@ private:
 	}
 
 	void LockCaughtError() noexcept {
+		period_buffer.Clear();
+
 		const std::lock_guard<Mutex> lock(mutex);
 		error = std::current_exception();
 		active = false;