diff --git a/packages/node_modules/@node-red/editor-client/src/js/nodes.js b/packages/node_modules/@node-red/editor-client/src/js/nodes.js
index 865636b24..94bdbfcf7 100644
--- a/packages/node_modules/@node-red/editor-client/src/js/nodes.js
+++ b/packages/node_modules/@node-red/editor-client/src/js/nodes.js
@@ -2095,16 +2095,27 @@ RED.nodes = (function() {
                     } else if (n.type.substring(0,7) === "subflow") {
                         var parentId = n.type.split(":")[1];
                         var subflow = subflow_denylist[parentId]||subflow_map[parentId]||getSubflow(parentId);
-                        if (createNewIds || options.importMap[n.id] === "copy") {
-                            parentId = subflow.id;
-                            node.type = "subflow:"+parentId;
-                            node._def = registry.getNodeType(node.type);
-                            delete node.i;
+                        if (!subflow){
+                            node._def = {
+                                color:"#fee",
+                                defaults: {},
+                                label: "unknown: "+n.type,
+                                labelStyle: "red-ui-flow-node-label-italic",
+                                outputs: n.outputs|| (n.wires && n.wires.length) || 0,
+                                set: registry.getNodeSet("node-red/unknown")
+                            }
+                        } else {
+                            if (createNewIds || options.importMap[n.id] === "copy") {
+                                parentId = subflow.id;
+                                node.type = "subflow:"+parentId;
+                                node._def = registry.getNodeType(node.type);
+                                delete node.i;
+                            }
+                            node.name = n.name;
+                            node.outputs = subflow.out.length;
+                            node.inputs = subflow.in.length;
+                            node.env = n.env;
                         }
-                        node.name = n.name;
-                        node.outputs = subflow.out.length;
-                        node.inputs = subflow.in.length;
-                        node.env = n.env;
                     } else if (n.type === 'junction') {
                          node._def = {defaults:{}}
                          node._config.x = node.x
diff --git a/packages/node_modules/@node-red/editor-client/src/js/ui/editor.js b/packages/node_modules/@node-red/editor-client/src/js/ui/editor.js
index da7954625..188819734 100644
--- a/packages/node_modules/@node-red/editor-client/src/js/ui/editor.js
+++ b/packages/node_modules/@node-red/editor-client/src/js/ui/editor.js
@@ -45,11 +45,13 @@ RED.editor = (function() {
         var hasChanged;
         if (node.type.indexOf("subflow:")===0) {
             subflow = RED.nodes.subflow(node.type.substring(8));
-            isValid = subflow.valid;
-            hasChanged = subflow.changed;
-            if (isValid === undefined) {
-                isValid = validateNode(subflow);
+            if (subflow){
+                isValid = subflow.valid;
                 hasChanged = subflow.changed;
+                if (isValid === undefined) {
+                    isValid = validateNode(subflow);
+                    hasChanged = subflow.changed;
+                }
             }
             validationErrors = validateNodeProperties(node, node._def.defaults, node);
             node.valid = isValid && validationErrors.length === 0;
diff --git a/packages/node_modules/@node-red/runtime/lib/flows/util.js b/packages/node_modules/@node-red/runtime/lib/flows/util.js
index 7c98fc041..83665b589 100644
--- a/packages/node_modules/@node-red/runtime/lib/flows/util.js
+++ b/packages/node_modules/@node-red/runtime/lib/flows/util.js
@@ -199,7 +199,9 @@ function parseConfig(config) {
                if (subflowDetails) {
                    var subflowType = subflowDetails[1]
                    n.subflow = subflowType;
-                   flow.subflows[subflowType].instances.push(n)
+                   if (flow.subflows[subflowType]) {
+                       flow.subflows[subflowType].instances.push(n)
+                   }
                }
                if (container) {
                    container.nodes[n.id] = n;