diff --git a/client/src/data-provider/queries.ts b/client/src/data-provider/queries.ts
index 8f2b702a3b..866e25a262 100644
--- a/client/src/data-provider/queries.ts
+++ b/client/src/data-provider/queries.ts
@@ -31,7 +31,7 @@ import type {
   SharedLinksResponse,
 } from 'librechat-data-provider';
 import type { ConversationCursorData } from '~/utils/convos';
-import { findConversationInInfinite } from '~/utils';
+import { findConversationInInfinite, isNotFoundError } from '~/utils';
 
 export const useGetPresetsQuery = (
   config?: UseQueryOptions<TPreset[]>,
@@ -71,6 +71,12 @@ export const useGetConvoIdQuery = (
       refetchOnWindowFocus: false,
       refetchOnReconnect: false,
       refetchOnMount: false,
+      retry: (failureCount, error) => {
+        if (isNotFoundError(error)) {
+          return false;
+        }
+        return failureCount < 3;
+      },
       ...config,
     },
   );
diff --git a/client/src/locales/en/translation.json b/client/src/locales/en/translation.json
index a9f8805d9b..e0dad68431 100644
--- a/client/src/locales/en/translation.json
+++ b/client/src/locales/en/translation.json
@@ -842,6 +842,7 @@
   "com_ui_controls": "Controls",
   "com_ui_conversation": "conversation",
   "com_ui_conversation_label": "{{title}} conversation",
+  "com_ui_conversation_not_found": "Conversation not found",
   "com_ui_conversations": "conversations",
   "com_ui_convo_archived": "Conversation archived",
   "com_ui_convo_delete_error": "Failed to delete conversation",
diff --git a/client/src/routes/ChatRoute.tsx b/client/src/routes/ChatRoute.tsx
index 0670ee1e85..c8fea73470 100644
--- a/client/src/routes/ChatRoute.tsx
+++ b/client/src/routes/ChatRoute.tsx
@@ -1,15 +1,22 @@
 import { useEffect } from 'react';
-import { Spinner } from '@librechat/client';
 import { useParams } from 'react-router-dom';
 import { useRecoilCallback, useRecoilValue } from 'recoil';
+import { Spinner, useToastContext } from '@librechat/client';
 import { Constants, EModelEndpoint } from 'librechat-data-provider';
 import { useGetModelsQuery } from 'librechat-data-provider/react-query';
 import type { TPreset } from 'librechat-data-provider';
+import {
+  useNewConvo,
+  useAppStartup,
+  useAssistantListMap,
+  useIdChangeEffect,
+  useLocalize,
+} from '~/hooks';
 import { useGetConvoIdQuery, useGetStartupConfig, useGetEndpointsQuery } from '~/data-provider';
-import { useNewConvo, useAppStartup, useAssistantListMap, useIdChangeEffect } from '~/hooks';
-import { getDefaultModelSpec, getModelSpecPreset, logger } from '~/utils';
+import { getDefaultModelSpec, getModelSpecPreset, logger, isNotFoundError } from '~/utils';
 import { ToolCallsMapProvider } from '~/Providers';
 import ChatView from '~/components/Chat/ChatView';
+import { NotificationSeverity } from '~/common';
 import useAuthRedirect from './useAuthRedirect';
 import temporaryStore from '~/store/temporary';
 import store from '~/store';
@@ -33,6 +40,8 @@ export default function ChatRoute() {
   useIdChangeEffect(conversationId);
   const { hasSetConversation, conversation } = store.useCreateConversationAtom(index);
   const { newConversation } = useNewConvo();
+  const { showToast } = useToastContext();
+  const localize = useLocalize();
 
   const modelsQuery = useGetModelsQuery({
     enabled: isAuthenticated,
@@ -92,6 +101,29 @@ export default function ChatRoute() {
         keepLatestMessage: true,
       });
       hasSetConversation.current = true;
+    } else if (
+      conversationId &&
+      endpointsQuery.data &&
+      modelsQuery.data &&
+      initialConvoQuery.isError &&
+      isNotFoundError(initialConvoQuery.error)
+    ) {
+      const result = getDefaultModelSpec(startupConfig);
+      const spec = result?.default ?? result?.last;
+      showToast({
+        message: localize('com_ui_conversation_not_found'),
+        severity: NotificationSeverity.WARNING,
+      });
+      logger.log(
+        'conversation',
+        'ChatRoute initialConvoQuery isNotFoundError',
+        initialConvoQuery.error,
+      );
+      newConversation({
+        modelsData: modelsQuery.data,
+        ...(spec ? { preset: getModelSpecPreset(spec) } : {}),
+      });
+      hasSetConversation.current = true;
     } else if (
       conversationId === Constants.NEW_CONVO &&
       assistantListMap[EModelEndpoint.assistants] &&
@@ -125,6 +157,7 @@ export default function ChatRoute() {
     roles,
     startupConfig,
     initialConvoQuery.data,
+    initialConvoQuery.isError,
     endpointsQuery.data,
     modelsQuery.data,
     assistantListMap,
diff --git a/client/src/utils/errors.ts b/client/src/utils/errors.ts
new file mode 100644
index 0000000000..04666c5313
--- /dev/null
+++ b/client/src/utils/errors.ts
@@ -0,0 +1,21 @@
+import axios from 'axios';
+
+/**
+ * Returns the HTTP response status code from an error, regardless of the
+ * HTTP client used.  Handles Axios errors first, then falls back to checking
+ * for a plain `status` property so callers never need to import axios.
+ */
+export const getResponseStatus = (error: unknown): number | undefined => {
+  if (axios.isAxiosError(error)) {
+    return error.response?.status;
+  }
+  if (error != null && typeof error === 'object' && 'status' in error) {
+    const { status } = error as { status: unknown };
+    if (typeof status === 'number') {
+      return status;
+    }
+  }
+  return undefined;
+};
+
+export const isNotFoundError = (error: unknown): boolean => getResponseStatus(error) === 404;
diff --git a/client/src/utils/index.ts b/client/src/utils/index.ts
index eede48f244..b8117b2677 100644
--- a/client/src/utils/index.ts
+++ b/client/src/utils/index.ts
@@ -3,6 +3,7 @@ import type { UIActionResult } from '@mcp-ui/client';
 import { TAskFunction } from '~/common';
 import logger from './logger';
 
+export * from './errors';
 export * from './map';
 export * from './json';
 export * from './files';