diff --git a/client/src/components/Nav/ExportConversation/ExportModal.tsx b/client/src/components/Nav/ExportConversation/ExportModal.tsx
index f9cd73875c..4303856e57 100644
--- a/client/src/components/Nav/ExportConversation/ExportModal.tsx
+++ b/client/src/components/Nav/ExportConversation/ExportModal.tsx
@@ -11,6 +11,7 @@ import {
 } from '@librechat/client';
 import type { TConversation } from 'librechat-data-provider';
 import { useLocalize, useExportConversation } from '~/hooks';
+import { normalizeExportFilename } from '~/utils';
 
 const TYPE_OPTIONS = [
   { value: 'screenshot', label: 'screenshot (.png)' },
@@ -72,7 +73,7 @@ export default function ExportModal({
 
   const { exportConversation } = useExportConversation({
     conversation,
-    filename: filenamify(filename),
+    filename: normalizeExportFilename(filenamify(filename)),
     type,
     includeOptions,
     exportBranches,
diff --git a/client/src/hooks/Conversations/usePresets.ts b/client/src/hooks/Conversations/usePresets.ts
index 5ead899004..93929fef10 100644
--- a/client/src/hooks/Conversations/usePresets.ts
+++ b/client/src/hooks/Conversations/usePresets.ts
@@ -1,18 +1,23 @@
+import { useCallback, useEffect, useRef, useState } from 'react';
 import filenamify from 'filenamify';
 import exportFromJSON from 'export-from-json';
 import { useToastContext } from '@librechat/client';
 import { QueryKeys } from 'librechat-data-provider';
 import { useQueryClient } from '@tanstack/react-query';
-import { useCallback, useEffect, useRef, useState } from 'react';
 import { useRecoilState, useSetRecoilState, useRecoilValue } from 'recoil';
 import { useCreatePresetMutation, useGetModelsQuery } from 'librechat-data-provider/react-query';
 import type { TPreset, TEndpointsConfig } from 'librechat-data-provider';
+import {
+  normalizeExportFilename,
+  removeUnavailableTools,
+  getConvoSwitchLogic,
+  cleanupPreset,
+} from '~/utils';
 import {
   useUpdatePresetMutation,
   useDeletePresetMutation,
   useGetPresetsQuery,
 } from '~/data-provider';
-import { cleanupPreset, removeUnavailableTools, getConvoSwitchLogic } from '~/utils';
 import useGetConversation from '~/hooks/Conversations/useGetConversation';
 import useDefaultConvo from '~/hooks/Conversations/useDefaultConvo';
 import { useAuthContext } from '~/hooks/AuthContext';
@@ -264,7 +269,7 @@ export default function usePresets(index = 0) {
     if (!preset) {
       return;
     }
-    const fileName = filenamify(preset.title || 'preset');
+    const fileName = normalizeExportFilename(filenamify(preset.title || 'preset'));
     exportFromJSON({
       data: cleanupPreset({ preset }),
       fileName,
diff --git a/client/src/utils/files.spec.ts b/client/src/utils/files.spec.ts
new file mode 100644
index 0000000000..49c150b2bf
--- /dev/null
+++ b/client/src/utils/files.spec.ts
@@ -0,0 +1,26 @@
+import { normalizeExportFilename } from './files';
+
+describe('normalizeExportFilename', () => {
+  it('replaces every whitespace run with a single underscore', () => {
+    expect(normalizeExportFilename('Word1 Word2 Word3')).toBe('Word1_Word2_Word3');
+  });
+
+  it('collapses consecutive whitespace into one underscore', () => {
+    expect(normalizeExportFilename('Word1  Word2\tWord3')).toBe('Word1_Word2_Word3');
+  });
+
+  it('leaves filenames without whitespace unchanged', () => {
+    expect(normalizeExportFilename('single-word_name')).toBe('single-word_name');
+  });
+
+  it('handles an empty string', () => {
+    expect(normalizeExportFilename('')).toBe('');
+  });
+
+  it('never leaves whitespace, so downstream whitespace-based formatters are no-ops', () => {
+    const inputs = ['Word1 Word2 Word3', ' leading', 'trailing ', 'tab\there', 'a  b   c'];
+    for (const input of inputs) {
+      expect(normalizeExportFilename(input)).not.toMatch(/\s/);
+    }
+  });
+});
diff --git a/client/src/utils/files.ts b/client/src/utils/files.ts
index b680a18c2d..d575f919b4 100644
--- a/client/src/utils/files.ts
+++ b/client/src/utils/files.ts
@@ -439,3 +439,12 @@ export function sortPagesByRelevance(
   }
   return [...pages].sort((a, b) => (pageRelevance[b] || 0) - (pageRelevance[a] || 0));
 }
+
+/**
+ * Collapses whitespace runs to underscores so export filenames come out
+ * identical across all export formats: `export-from-json`'s default formatter
+ * only replaces the first whitespace run, while direct downloads replace none.
+ */
+export function normalizeExportFilename(filename: string): string {
+  return filename.replace(/\s+/g, '_');
+}