diff --git a/src/components/nostr/kinds/RepositoryFilesSection.tsx b/src/components/nostr/kinds/RepositoryFilesSection.tsx
index 01130b9..8acfef7 100644
--- a/src/components/nostr/kinds/RepositoryFilesSection.tsx
+++ b/src/components/nostr/kinds/RepositoryFilesSection.tsx
@@ -1,4 +1,4 @@
-import { useState, useMemo } from "react";
+import { useState } from "react";
 import { FolderGit2, AlertCircle, FileQuestion, Binary } from "lucide-react";
 import { useGitTree } from "@/hooks/useGitTree";
 import { useGitBlob } from "@/hooks/useGitBlob";
@@ -67,10 +67,9 @@ export function RepositoryFilesSection({
   });
 
   // Get the language for syntax highlighting from the file extension
-  const language = useMemo(() => {
-    if (!selectedFile) return null;
-    return getExtension(selectedFile.name) || null;
-  }, [selectedFile]);
+  const language = selectedFile
+    ? getExtension(selectedFile.name) || null
+    : null;
 
   const handleFileSelect = (file: SelectedFile) => {
     setSelectedFile(file);
diff --git a/src/components/ui/FileTreeView.tsx b/src/components/ui/FileTreeView.tsx
index 46a0615..7dd3716 100644
--- a/src/components/ui/FileTreeView.tsx
+++ b/src/components/ui/FileTreeView.tsx
@@ -237,31 +237,37 @@ function TreeContents({
 
   return (
     <div>
-      {sortedEntries.dirs.map((dir) => (
-        <TreeNode
-          key={dir.hash}
-          name={dir.name}
-          hash={dir.hash}
-          path={basePath ? `${basePath}/${dir.name}` : dir.name}
-          isDirectory={true}
-          content={dir.content}
-          onFileSelect={onFileSelect}
-          selectedPath={selectedPath}
-          depth={depth}
-        />
-      ))}
-      {sortedEntries.files.map((file) => (
-        <TreeNode
-          key={file.hash}
-          name={file.name}
-          hash={file.hash}
-          path={basePath ? `${basePath}/${file.name}` : file.name}
-          isDirectory={false}
-          onFileSelect={onFileSelect}
-          selectedPath={selectedPath}
-          depth={depth}
-        />
-      ))}
+      {sortedEntries.dirs.map((dir) => {
+        const dirPath = basePath ? `${basePath}/${dir.name}` : dir.name;
+        return (
+          <TreeNode
+            key={dirPath}
+            name={dir.name}
+            hash={dir.hash}
+            path={dirPath}
+            isDirectory={true}
+            content={dir.content}
+            onFileSelect={onFileSelect}
+            selectedPath={selectedPath}
+            depth={depth}
+          />
+        );
+      })}
+      {sortedEntries.files.map((file) => {
+        const filePath = basePath ? `${basePath}/${file.name}` : file.name;
+        return (
+          <TreeNode
+            key={filePath}
+            name={file.name}
+            hash={file.hash}
+            path={filePath}
+            isDirectory={false}
+            onFileSelect={onFileSelect}
+            selectedPath={selectedPath}
+            depth={depth}
+          />
+        );
+      })}
     </div>
   );
 }
diff --git a/src/hooks/useGitBlob.ts b/src/hooks/useGitBlob.ts
index 89a8df2..25bdc16 100644
--- a/src/hooks/useGitBlob.ts
+++ b/src/hooks/useGitBlob.ts
@@ -1,4 +1,4 @@
-import { useState, useEffect, useCallback } from "react";
+import { useState, useEffect, useRef, useCallback } from "react";
 import { getObject } from "@fiatjaf/git-natural-api";
 
 interface UseGitBlobOptions {
@@ -61,6 +61,9 @@ export function useGitBlob({
   const [error, setError] = useState<Error | null>(null);
   const [isBinary, setIsBinary] = useState(false);
 
+  // Track mounted state to prevent state updates after unmount
+  const isMountedRef = useRef(true);
+
   const fetchBlob = useCallback(async () => {
     if (!serverUrl || !hash) {
       return;
@@ -75,6 +78,8 @@ export function useGitBlob({
     try {
       const object = await getObject(serverUrl, hash);
 
+      if (!isMountedRef.current) return;
+
       if (!object || !object.data) {
         throw new Error("Empty or invalid blob");
       }
@@ -97,18 +102,28 @@ export function useGitBlob({
         }
       }
     } catch (e) {
+      if (!isMountedRef.current) return;
+
       const err = e instanceof Error ? e : new Error(String(e));
       console.warn(`[useGitBlob] Failed to fetch blob ${hash}:`, err.message);
       setError(err);
     } finally {
-      setLoading(false);
+      if (isMountedRef.current) {
+        setLoading(false);
+      }
     }
   }, [serverUrl, hash]);
 
   useEffect(() => {
+    isMountedRef.current = true;
+
     if (enabled && serverUrl && hash) {
       fetchBlob();
     }
+
+    return () => {
+      isMountedRef.current = false;
+    };
   }, [enabled, serverUrl, hash, fetchBlob]);
 
   return {
diff --git a/src/hooks/useGitTree.ts b/src/hooks/useGitTree.ts
index fdad32b..1c6a0a6 100644
--- a/src/hooks/useGitTree.ts
+++ b/src/hooks/useGitTree.ts
@@ -1,9 +1,10 @@
-import { useState, useEffect, useCallback } from "react";
+import { useState, useEffect, useRef, useCallback } from "react";
 import {
   getInfoRefs,
   getDirectoryTreeAt,
   MissingCapability,
 } from "@fiatjaf/git-natural-api";
+import { useStableArray } from "@/hooks/useStable";
 import type { DirectoryTree } from "@/lib/git-types";
 
 interface UseGitTreeOptions {
@@ -51,8 +52,14 @@ export function useGitTree({
   const [error, setError] = useState<Error | null>(null);
   const [serverUrl, setServerUrl] = useState<string | null>(null);
 
+  // Stabilize cloneUrls to prevent unnecessary re-fetches
+  const stableCloneUrls = useStableArray(cloneUrls);
+
+  // Track mounted state to prevent state updates after unmount
+  const isMountedRef = useRef(true);
+
   const fetchTree = useCallback(async () => {
-    if (cloneUrls.length === 0) {
+    if (stableCloneUrls.length === 0) {
       setError(new Error("No clone URLs provided"));
       return;
     }
@@ -64,11 +71,16 @@ export function useGitTree({
 
     const errors: Error[] = [];
 
-    for (const url of cloneUrls) {
+    for (const url of stableCloneUrls) {
+      // Check if still mounted before each iteration
+      if (!isMountedRef.current) return;
+
       try {
         // Get server info to check capabilities and resolve refs
         const info = await getInfoRefs(url);
 
+        if (!isMountedRef.current) return;
+
         // Only use servers that support filter capability (lightweight fetch)
         // Skip servers that would require downloading all blobs
         if (!info.capabilities.includes("filter")) {
@@ -105,6 +117,8 @@ export function useGitTree({
         // Fetch the tree using lightweight filter (tree only, no blobs)
         const fetchedTree = await getDirectoryTreeAt(url, resolvedRef);
 
+        if (!isMountedRef.current) return;
+
         setTree(fetchedTree);
         setServerUrl(url);
         setLoading(false);
@@ -128,20 +142,28 @@ export function useGitTree({
       }
     }
 
+    if (!isMountedRef.current) return;
+
     // All URLs failed
     const message =
       errors.length === 1
         ? errors[0].message
-        : `All ${cloneUrls.length} servers failed`;
+        : `All ${stableCloneUrls.length} servers failed`;
     setError(new Error(message));
     setLoading(false);
-  }, [cloneUrls, ref]);
+  }, [stableCloneUrls, ref]);
 
   useEffect(() => {
-    if (enabled && cloneUrls.length > 0) {
+    isMountedRef.current = true;
+
+    if (enabled && stableCloneUrls.length > 0) {
       fetchTree();
     }
-  }, [enabled, fetchTree, cloneUrls.length]);
+
+    return () => {
+      isMountedRef.current = false;
+    };
+  }, [enabled, fetchTree, stableCloneUrls]);
 
   return {
     tree,
diff --git a/src/lib/shiki.ts b/src/lib/shiki.ts
index 8f7a7e3..718dd93 100644
--- a/src/lib/shiki.ts
+++ b/src/lib/shiki.ts
@@ -9,6 +9,7 @@ import { createOnigurumaEngine } from "shiki/engine/oniguruma";
 let highlighter: HighlighterCore | null = null;
 let highlighterPromise: Promise<HighlighterCore> | null = null;
 const loadedLanguages = new Set<string>();
+const failedLanguages = new Set<string>();
 
 /**
  * Grimoire dark theme - minimalistic grayscale with high contrast
@@ -461,6 +462,7 @@ export async function getHighlighter(): Promise<HighlighterCore> {
  */
 async function loadLanguage(lang: string): Promise<boolean> {
   if (lang === "text" || loadedLanguages.has(lang)) return true;
+  if (failedLanguages.has(lang)) return false;
 
   const hl = await getHighlighter();
 
@@ -471,7 +473,8 @@ async function loadLanguage(lang: string): Promise<boolean> {
     loadedLanguages.add(lang);
     return true;
   } catch {
-    // Language not available
+    // Language not available - track to avoid repeated warnings
+    failedLanguages.add(lang);
     console.warn(
       `[shiki] Language "${lang}" not available, falling back to plaintext`,
     );