diff --git a/node/modules/graphsync.go b/node/modules/graphsync.go
index 656e19b82..4197d6ca2 100644
--- a/node/modules/graphsync.go
+++ b/node/modules/graphsync.go
@@ -70,8 +70,10 @@ func (p *LinkSystemProv) LinkSys() *ipld.LinkSystem {
 }
 
 func SetLinkSystem(proxy *LinkSystemProv, prov provider.Interface) {
-	e := prov.(*engine.Engine)
-	proxy.LinkSystem = e.LinkSystem()
+	e, ok := prov.(*engine.Engine)
+	if ok {
+		proxy.LinkSystem = e.LinkSystem()
+	}
 }
 
 // RetrievalGraphsync creates a graphsync instance used to serve retrievals.
diff --git a/retrievalmarket/server/gsunpaidretrieval.go b/retrievalmarket/server/gsunpaidretrieval.go
index 2f97a6289..6740a3d2d 100644
--- a/retrievalmarket/server/gsunpaidretrieval.go
+++ b/retrievalmarket/server/gsunpaidretrieval.go
@@ -120,7 +120,7 @@ func (g *GraphsyncUnpaidRetrieval) Start(ctx context.Context) error {
 	g.ctx = ctx
 	g.validator.ctx = ctx
 
-	if g.linkSystem != nil {
+	if g.linkSystem != nil && g.linkSystem.LinkSys() != nil {
 		// The index provider uses graphsync to fetch advertisements.
 		// We need to tell graphsync to use a different IPLD Link System to provide
 		// the advertisements (instead of using the blockstore).