diff --git a/apps/x/apps/renderer/src/App.tsx b/apps/x/apps/renderer/src/App.tsx
index 4fd75591..a6364308 100644
--- a/apps/x/apps/renderer/src/App.tsx
+++ b/apps/x/apps/renderer/src/App.tsx
@@ -17,7 +17,8 @@ import { ImageFileViewer } from '@/components/image-file-viewer';
 import { VideoFileViewer } from '@/components/video-file-viewer';
 import { AudioFileViewer } from '@/components/audio-file-viewer';
 import { PersistentViewerCache } from '@/components/persistent-viewer-cache';
-import { getViewerType, isMediaPath, isCacheableViewerPath } from '@/lib/file-types';
+import { UnsupportedFileViewer } from '@/components/unsupported-file-viewer';
+import { getViewerType, isCacheableViewerPath } from '@/lib/file-types';
 import { useDebounce } from './hooks/use-debounce';
 import { SidebarContentPanel } from '@/components/sidebar-content';
 import { SuggestedTopicsView } from '@/components/suggested-topics-view';
@@ -1429,10 +1430,10 @@ function App() {
     }
     const requestId = (fileLoadRequestIdRef.current += 1)
     const pathToLoad = selectedPath
-    // Media viewers (HTML, image, video, audio, PDF) self-load via app:// protocol.
-    // Skip the generic UTF-8 loader so we don't trash fileContent with binary
-    // bytes or double-fetch large files.
-    if (isMediaPath(pathToLoad)) {
+    // Only the markdown editor still consumes fileContent. Every other viewer
+    // (media + UnsupportedFileViewer) self-loads, so skip the generic UTF-8
+    // loader to avoid double-fetching and to avoid slurping binary bytes.
+    if (!pathToLoad.endsWith('.md')) {
       setFileContent('')
       return
     }
@@ -4853,10 +4854,8 @@ function App() {
                     <AudioFileViewer path={selectedPath} />
                   </div>
                 ) : (
-                  <div className="flex-1 overflow-auto p-4">
-                    <pre className="text-sm font-mono text-foreground whitespace-pre-wrap">
-                      {fileContent || 'Loading...'}
-                    </pre>
+                  <div className="flex-1 min-h-0 overflow-hidden">
+                    <UnsupportedFileViewer path={selectedPath} />
                   </div>
                 )
                 )}
diff --git a/apps/x/apps/renderer/src/components/unsupported-file-viewer.tsx b/apps/x/apps/renderer/src/components/unsupported-file-viewer.tsx
new file mode 100644
index 00000000..474d7dba
--- /dev/null
+++ b/apps/x/apps/renderer/src/components/unsupported-file-viewer.tsx
@@ -0,0 +1,149 @@
+import { useEffect, useState } from 'react'
+import { ExternalLinkIcon, FileIcon, FileTextIcon, Loader2Icon } from 'lucide-react'
+
+const TEXT_FALLBACK_MAX_BYTES = 1 * 1024 * 1024 // 1 MB
+
+interface UnsupportedFileViewerProps {
+  path: string
+}
+
+type State =
+  | { kind: 'loading' }
+  | { kind: 'ready'; sizeBytes: number; canShowAsText: boolean }
+  | { kind: 'error'; message: string }
+
+function basename(path: string): string {
+  const idx = path.lastIndexOf('/')
+  return idx >= 0 ? path.slice(idx + 1) : path
+}
+
+function extensionLabel(path: string): string {
+  const name = basename(path)
+  const dot = name.lastIndexOf('.')
+  if (dot < 0) return 'No extension'
+  return name.slice(dot + 1).toUpperCase()
+}
+
+function formatSize(bytes: number): string {
+  if (bytes < 1024) return `${bytes} B`
+  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`
+  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`
+}
+
+export function UnsupportedFileViewer({ path }: UnsupportedFileViewerProps) {
+  const [state, setState] = useState<State>({ kind: 'loading' })
+  const [textContent, setTextContent] = useState<string | null>(null)
+
+  useEffect(() => {
+    let cancelled = false
+    setState({ kind: 'loading' })
+    setTextContent(null)
+
+    ;(async () => {
+      try {
+        const stat = await window.ipc.invoke('workspace:stat', { path })
+        if (cancelled) return
+        if (stat.kind !== 'file') {
+          setState({ kind: 'error', message: 'Selected path is not a file.' })
+          return
+        }
+        setState({
+          kind: 'ready',
+          sizeBytes: stat.size,
+          canShowAsText: stat.size <= TEXT_FALLBACK_MAX_BYTES,
+        })
+      } catch (err) {
+        if (cancelled) return
+        const message = err instanceof Error ? err.message : String(err)
+        setState({ kind: 'error', message })
+      }
+    })()
+
+    return () => {
+      cancelled = true
+    }
+  }, [path])
+
+  async function loadAsText() {
+    try {
+      const result = await window.ipc.invoke('workspace:readFile', { path })
+      setTextContent(result.data)
+    } catch (err) {
+      const message = err instanceof Error ? err.message : String(err)
+      setTextContent(`Failed to read as text: ${message}`)
+    }
+  }
+
+  if (state.kind === 'loading') {
+    return (
+      <div className="flex h-full w-full flex-col items-center justify-center gap-3 text-muted-foreground">
+        <Loader2Icon className="size-6 animate-spin" />
+      </div>
+    )
+  }
+
+  if (state.kind === 'error') {
+    return (
+      <div className="flex h-full w-full flex-col items-center justify-center gap-2 px-6 text-center text-muted-foreground">
+        <FileIcon className="size-6" />
+        <p className="text-sm font-medium text-foreground">Could not open</p>
+        <p className="max-w-md text-xs">{state.message}</p>
+      </div>
+    )
+  }
+
+  if (textContent !== null) {
+    return (
+      <div className="flex h-full w-full flex-col">
+        <div className="flex items-center justify-between border-b border-border bg-muted/30 px-4 py-2 text-xs text-muted-foreground">
+          <span className="truncate">{basename(path)} · plain text view</span>
+          <button
+            type="button"
+            onClick={() => setTextContent(null)}
+            className="text-foreground hover:underline"
+          >
+            Hide
+          </button>
+        </div>
+        <div className="flex-1 overflow-auto p-4">
+          <pre className="text-sm font-mono text-foreground whitespace-pre-wrap">{textContent}</pre>
+        </div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="flex h-full w-full flex-col items-center justify-center gap-3 px-6 text-center text-muted-foreground">
+      <FileIcon className="size-10 text-muted-foreground" />
+      <p className="max-w-md truncate text-sm font-medium text-foreground" title={path}>
+        {basename(path)}
+      </p>
+      <p className="text-xs">
+        {extensionLabel(path)} · {formatSize(state.sizeBytes)}
+      </p>
+      <p className="max-w-md text-xs">No in-app preview for this file type.</p>
+      <div className="flex items-center gap-2">
+        <button
+          type="button"
+          onClick={() => {
+            void window.ipc.invoke('shell:openPath', { path })
+          }}
+          className="inline-flex items-center gap-1.5 rounded-md border border-border bg-background px-3 py-1.5 text-xs font-medium text-foreground hover:bg-accent"
+        >
+          <ExternalLinkIcon className="size-3.5" />
+          Open in system
+        </button>
+        {state.canShowAsText && (
+          <button
+            type="button"
+            onClick={() => void loadAsText()}
+            className="inline-flex items-center gap-1.5 rounded-md border border-border bg-background px-3 py-1.5 text-xs font-medium text-foreground hover:bg-accent"
+          >
+            <FileTextIcon className="size-3.5" />
+            Show as plain text
+          </button>
+        )}
+      </div>
+    </div>
+  )
+}