diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8fc60a5a4..dc377fc64 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,13 +12,16 @@ You can also check the
 ## Unreleased
 
 - Fixes
+
   - Correctly set CSP headers for index pages
   - Harden markdown renderer sanitization
+  - Make measure id optional for symbol layers in map charts. Fixes issues with
+    invalid view configuration that prevents that users could copy and edit an
+    existing visualization
 
 - Maintenance
   - Add dev-container support
 
-
 ## 6.5.0 – 2026-06-01
 
 - Features
diff --git a/app/charts/index.ts b/app/charts/index.ts
index 7083238cc..a66b13997 100644
--- a/app/charts/index.ts
+++ b/app/charts/index.ts
@@ -59,7 +59,6 @@ import {
   TableFields,
 } from "@/config-types";
 import { mapValueIrisToColor } from "@/configurator/components/ui-helpers";
-import { FIELD_VALUE_NONE } from "@/configurator/constants";
 import {
   Component,
   Dimension,
@@ -321,7 +320,7 @@ const getInitialSymbolLayer = ({
 }): MapSymbolLayer => {
   return {
     componentId: component.id,
-    measureId: measure?.id ?? FIELD_VALUE_NONE,
+    measureId: measure?.id,
     color: DEFAULT_FIXED_COLOR_FIELD,
   };
 };
diff --git a/app/charts/shared/chart-helpers.tsx b/app/charts/shared/chart-helpers.tsx
index ec707cd90..2cae765c4 100644
--- a/app/charts/shared/chart-helpers.tsx
+++ b/app/charts/shared/chart-helpers.tsx
@@ -225,7 +225,7 @@ const getMapChartConfigAdditionalFieldIds = ({ fields }: MapConfig) => {
   }
 
   if (symbolLayer) {
-    if (symbolLayer.measureId !== FIELD_VALUE_NONE) {
+    if (symbolLayer.measureId && symbolLayer.measureId !== FIELD_VALUE_NONE) {
       additionalFields.push(symbolLayer.measureId);
     }
 
diff --git a/app/config-types.ts b/app/config-types.ts
index 4674a386b..6a30063c0 100644
--- a/app/config-types.ts
+++ b/app/config-types.ts
@@ -948,13 +948,21 @@ const MapAreaLayer = t.type({
 });
 export type MapAreaLayer = t.TypeOf<typeof MapAreaLayer>;
 
-const MapSymbolLayer = t.type({
-  componentId: t.string,
-  /** Symbol radius (size) */
-  measureId: t.string,
-  // FIXME: convert to new color field type
-  color: t.union([FixedColorField, CategoricalColorField, NumericalColorField]),
-});
+const MapSymbolLayer = t.intersection([
+  t.type({
+    componentId: t.string,
+    // FIXME: convert to new color field type
+    color: t.union([
+      FixedColorField,
+      CategoricalColorField,
+      NumericalColorField,
+    ]),
+  }),
+  t.partial({
+    /** Symbol radius (size) */
+    measureId: t.string,
+  }),
+]);
 export type MapSymbolLayer = t.TypeOf<typeof MapSymbolLayer>;
 
 const BaseCustomLayer = t.type({