1 files changed, 5 insertions, 0 deletions
diff --git a/src/state.c b/src/state.c
index e5c789b..9b44c42 100644
--- a/src/state.c
+++ b/src/state.c
@@ -192,6 +192,11 @@ store_callback(LV2_State_Handle handle,
                uint32_t         flags)
 {
 	LilvState* const state = (LilvState*)handle;
+
+	if (find_property((const LilvState*)handle, key)) {
+		return LV2_STATE_ERR_UNKNOWN; // TODO: Add status for duplicate keys
+	}
+
 	append_property(state, &state->props, key, value, size, type, flags);
 	return LV2_STATE_SUCCESS;
 }