diff --git a/light9/web/SyncedGraph.ts b/light9/web/SyncedGraph.ts
--- a/light9/web/SyncedGraph.ts
+++ b/light9/web/SyncedGraph.ts
@@ -51,7 +51,10 @@ export class SyncedGraph {
     this.cachedFloatValues = new Map(); // s + '|' + p -> number
     this.cachedUriValues = new Map(); // s + '|' + p -> Uri
 
-    this._applyPatch(patchToDeleteEntireGraph(this.graph));
+    const p = patchToDeleteEntireGraph(this.graph);
+    if (!p.isEmpty()) {
+      this._applyPatch(p);
+    }
     // if we had a Store already, this lets N3.Store free all its indices/etc
     this.graph = new N3.Store();
     this.rebuildPrefixFuncs(this.prefixes);