diff --git a/packages/react-components/react-virtualizer/library/etc/react-virtualizer.api.md b/packages/react-components/react-virtualizer/library/etc/react-virtualizer.api.md
index aa8396690534a..62e0171de50f1 100644
--- a/packages/react-components/react-virtualizer/library/etc/react-virtualizer.api.md
+++ b/packages/react-components/react-virtualizer/library/etc/react-virtualizer.api.md
@@ -80,7 +80,7 @@ export const useDynamicVirtualizerMeasure: <TElement extends HTMLElement>(virtua
     bufferItems: number;
     bufferSize: number;
     scrollRef: (instance: TElement | null) => void;
-    containerSizeRef: React_2.MutableRefObject<number>;
+    containerSizeRef: React_2.RefObject<number>;
 };
 
 // @public
diff --git a/packages/react-components/react-virtualizer/library/src/components/Virtualizer/Virtualizer.types.ts b/packages/react-components/react-virtualizer/library/src/components/Virtualizer/Virtualizer.types.ts
index f2b58e8e565d1..cd5661c86eec2 100644
--- a/packages/react-components/react-virtualizer/library/src/components/Virtualizer/Virtualizer.types.ts
+++ b/packages/react-components/react-virtualizer/library/src/components/Virtualizer/Virtualizer.types.ts
@@ -194,7 +194,7 @@ export type VirtualizerConfigProps = {
    * A ref that provides the size of container (vertical - height, horizontal - width), set by a resize observer.
    * Virtualizer Measure hooks provide a suitable reference.
    */
-  containerSizeRef: MutableRefObject<number>;
+  containerSizeRef: RefObject<number>;
 };
 
 export type VirtualizerProps = ComponentProps<Partial<VirtualizerSlots>> & VirtualizerConfigProps;
diff --git a/packages/react-components/react-virtualizer/library/src/components/Virtualizer/useVirtualizer.ts b/packages/react-components/react-virtualizer/library/src/components/Virtualizer/useVirtualizer.ts
index 6cc23146b5b71..bd6976b03c132 100644
--- a/packages/react-components/react-virtualizer/library/src/components/Virtualizer/useVirtualizer.ts
+++ b/packages/react-components/react-virtualizer/library/src/components/Virtualizer/useVirtualizer.ts
@@ -345,7 +345,7 @@ export function useVirtualizer_unstable(props: VirtualizerProps): VirtualizerSta
             // Ignore buffer size (IO offset)
             measurementPos -= bufferSize;
             // we hit the after buffer and detected the end of view, we need to find the start index.
-            measurementPos -= containerSizeRef.current;
+            measurementPos -= containerSizeRef.current ?? 0;
 
             // Calculate how far past the window bounds we are (this will be zero if IO is within window)
             const hOverflow = latestEntry.boundingClientRect.top - latestEntry.intersectionRect.top;
diff --git a/packages/react-components/react-virtualizer/library/src/hooks/useDynamicVirtualizerMeasure.ts b/packages/react-components/react-virtualizer/library/src/hooks/useDynamicVirtualizerMeasure.ts
index 2d509d667d0f6..f980e99e20425 100644
--- a/packages/react-components/react-virtualizer/library/src/hooks/useDynamicVirtualizerMeasure.ts
+++ b/packages/react-components/react-virtualizer/library/src/hooks/useDynamicVirtualizerMeasure.ts
@@ -15,7 +15,7 @@ export const useDynamicVirtualizerMeasure = <TElement extends HTMLElement>(
   bufferItems: number;
   bufferSize: number;
   scrollRef: (instance: TElement | null) => void;
-  containerSizeRef: React.MutableRefObject<number>;
+  containerSizeRef: React.RefObject<number>;
 } => {
   const {
     defaultItemSize,