diff --git a/intuita-webview/src/main/App.css b/intuita-webview/src/main/App.css
index fdab19d9..d3abbc51 100644
--- a/intuita-webview/src/main/App.css
+++ b/intuita-webview/src/main/App.css
@@ -65,3 +65,10 @@
 	height: 4em;
 	width: 100%;
 }
+
+.warning {
+	font-size: var(--type-ramp-base-font-size);
+	line-height: var(--type-ramp-base-line-height);
+	display: block;
+	color: var(--foreground);
+}
diff --git a/intuita-webview/src/main/App.tsx b/intuita-webview/src/main/App.tsx
index 8e671a05..04273242 100644
--- a/intuita-webview/src/main/App.tsx
+++ b/intuita-webview/src/main/App.tsx
@@ -90,7 +90,10 @@ function App() {
 	}, []);
 
 	useEffect(() => {
-		if (mainWebviewViewProps.toaster === null) {
+		if (
+			mainWebviewViewProps === null ||
+			mainWebviewViewProps.toaster === null
+		) {
 			return;
 		}
 
@@ -122,7 +125,7 @@ function App() {
 			kind: 'webview.main.setToaster',
 			value: null,
 		});
-	}, [mainWebviewViewProps.toaster]);
+	}, [mainWebviewViewProps, mainWebviewViewProps?.toaster]);
 
 	const handlePanelTabClick = (id: ActiveTabId) => {
 		vscode.postMessage({
@@ -131,6 +134,16 @@ function App() {
 		});
 	};
 
+	if (mainWebviewViewProps === null) {
+		return (
+			<main className="App" ref={ref}>
+				<p className="warning">
+					Open a workspace folder to use the Intuita VSCode Extension.
+				</p>
+			</main>
+		);
+	}
+
 	return (
 		<main className="App" ref={ref}>
 			<VSCodePanels
diff --git a/src/components/webview/MainProvider.ts b/src/components/webview/MainProvider.ts
index 8a48971d..af1420f0 100644
--- a/src/components/webview/MainProvider.ts
+++ b/src/components/webview/MainProvider.ts
@@ -217,7 +217,8 @@ export class MainViewProvider implements WebviewViewProvider {
 			}
 
 			if (
-				prevProps.activeTabId !== nextProps.activeTabId &&
+				nextProps !== null &&
+				prevProps?.activeTabId !== nextProps.activeTabId &&
 				nextProps.activeTabId === 'codemodRuns' &&
 				!nextProps.clearingInProgress
 			) {
diff --git a/src/selectors/selectMainWebviewViewProps.ts b/src/selectors/selectMainWebviewViewProps.ts
index 75e0be52..bbabfecb 100644
--- a/src/selectors/selectMainWebviewViewProps.ts
+++ b/src/selectors/selectMainWebviewViewProps.ts
@@ -12,6 +12,10 @@ export const selectMainWebviewViewProps = (
 	autocompleteItems: ReadonlyArray<string>,
 	executionQueue: ReadonlyArray<CodemodHash>,
 ) => {
+	if (rootUri === null) {
+		return null;
+	}
+
 	if (state.activeTabId === 'codemods') {
 		return {
 			activeTabId: state.activeTabId,