diff --git a/libretroshare/src/ft/ftchunkmap.cc b/libretroshare/src/ft/ftchunkmap.cc
index 5b28649e6..dc2800e76 100644
--- a/libretroshare/src/ft/ftchunkmap.cc
+++ b/libretroshare/src/ft/ftchunkmap.cc
@@ -326,7 +326,7 @@ uint32_t ChunkMap::getAvailableChunk(uint32_t start_location,const std::string&
 	{
 		SourceChunksInfo& pchunks(_peers_chunks_availability[peer_id]) ;
 
-		bool assume_availability = !rsTurtle->isTurtlePeer(peer_id) ;
+		bool assume_availability = !(rsTurtle!=NULL && rsTurtle->isTurtlePeer(peer_id)) ;
 
 		// Ok, we don't have the info, so two cases:
 		// 	- peer_id is a not a turtle peer, so he is considered having the full file source, so we init with a plain chunkmap