diff --git a/CHANGES b/CHANGES
index f9787a9..6e54b1e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+untagged yet (2015-06-26)
+    - bugfix: F source(s) unavailable message from IRRD was ignored
+
 0.1.31   (2015-06-23)
     - pipelining mode now counts buffered requests and issues dequeue
       when new request can overflow allocated buffer. So, bgpq3 shall no
diff --git a/bgpq_expander.c b/bgpq_expander.c
index f6f09fc..dcc10a5 100644
--- a/bgpq_expander.c
+++ b/bgpq_expander.c
@@ -390,7 +390,7 @@ bgpq_pipeline(FILE* f, int (*callback)(char*, void*), void* udata,
 		};
 	};
 
-	SX_DEBUG(debug_expander,"expander: sending '%s' (queued %i of %i)\n", 
+	SX_DEBUG(debug_expander,"expander: sending '%s' (queued %i of %i)\n",
 		request, d->qsize, d->socksize);
 
 	bp=malloc(sizeof(struct bgpq_prequest));
@@ -668,6 +668,11 @@ bgpq_expand(struct bgpq_expander* b)
 		snprintf(sources,sizeof(sources),"!s%s\n", b->sources);
 		fwrite(sources,strlen(sources),1,f);
 		fgets(sources,sizeof(sources),f);
+		if(sources[0]!='C') {
+			sx_report(SX_ERROR, "Invalid sources '%s': %s\n", b->sources,
+				sources);
+			exit(1);
+		};
 	};
 
 	if(b->identify) {