diff --git a/common/misc_utils.py b/common/misc_utils.py
index daebf4c8c..694b8b494 100644
--- a/common/misc_utils.py
+++ b/common/misc_utils.py
@@ -173,8 +173,8 @@ def install_mineru() -> None:
         Logging is used to indicate status.
     """
     # Check if MinerU is enabled
-    use_mineru = os.getenv("USE_MINERU", "").strip().lower()
-    if use_mineru == "false":
+    use_mineru = os.getenv("USE_MINERU", "false").strip().lower()
+    if use_mineru != "true":
         logging.info("USE_MINERU=%r. Skipping MinerU installation.", use_mineru)
         return
 
diff --git a/web/src/components/document-preview/doc-preview.tsx b/web/src/components/document-preview/doc-preview.tsx
index 470765f6e..5f8dd0cf9 100644
--- a/web/src/components/document-preview/doc-preview.tsx
+++ b/web/src/components/document-preview/doc-preview.tsx
@@ -1,7 +1,5 @@
 import message from '@/components/ui/message';
 import { Spin } from '@/components/ui/spin';
-import { Authorization } from '@/constants/authorization';
-import { getAuthorization } from '@/utils/authorization-util';
 import request from '@/utils/request';
 import classNames from 'classnames';
 import mammoth from 'mammoth';
@@ -16,22 +14,55 @@ export const DocPreviewer: React.FC<DocPreviewerProps> = ({
   className,
   url,
 }) => {
-  // const url = useGetDocumentUrl();
   const [htmlContent, setHtmlContent] = useState<string>('');
   const [loading, setLoading] = useState(false);
+
   const fetchDocument = async () => {
+    if (!url) return;
+
     setLoading(true);
+
     const res = await request(url, {
       method: 'GET',
       responseType: 'blob',
-      headers: { [Authorization]: getAuthorization() },
       onError: () => {
         message.error('Document parsing failed');
         console.error('Error loading document:', url);
       },
     });
+
     try {
-      const arrayBuffer = await res.data.arrayBuffer();
+      const blob: Blob = res.data;
+      const contentType: string =
+        blob.type || (res as any).headers?.['content-type'] || '';
+
+      // ---- Detect legacy .doc via MIME or URL ----
+      const cleanUrl = url.split(/[?#]/)[0].toLowerCase();
+      const isDocMime = /application\/msword/i.test(contentType);
+      const isLegacyDocByUrl =
+        cleanUrl.endsWith('.doc') && !cleanUrl.endsWith('.docx');
+      const isLegacyDoc = isDocMime || isLegacyDocByUrl;
+
+      if (isLegacyDoc) {
+        // Do not call mammoth and do not throw an error; instead, show a note in the preview area
+        setHtmlContent(`
+          <div class="flex h-full items-center justify-center">
+            <div class="border border-dashed border-border-normal rounded-xl p-8 max-w-2xl text-center">
+              <p class="text-2xl font-bold mb-4">
+                Preview not available for .doc files
+              </p>
+              <p class="italic text-sm text-muted-foreground leading-relaxed">
+                Mammoth does not support <code>.doc</code> documents.<br/>
+                Inline preview is unavailable.
+              </p>
+            </div>
+          </div>
+        `);
+        return;
+      }
+
+      // ---- Standard .docx preview path ----
+      const arrayBuffer = await blob.arrayBuffer();
       const result = await mammoth.convertToHtml(
         { arrayBuffer },
         { includeDefaultStyleMap: true },
@@ -43,10 +74,12 @@ export const DocPreviewer: React.FC<DocPreviewerProps> = ({
 
       setHtmlContent(styledContent);
     } catch (err) {
+      // Only errors from the mammoth conversion path should surface here
       message.error('Document parsing failed');
       console.error('Error parsing document:', err);
+    } finally {
+      setLoading(false);
     }
-    setLoading(false);
   };
 
   useEffect(() => {
@@ -54,6 +87,7 @@ export const DocPreviewer: React.FC<DocPreviewerProps> = ({
       fetchDocument();
     }
   }, [url]);
+
   return (
     <div
       className={classNames(