diff --git a/src/cli/runtime/serve-supervisor-relocation.test.ts b/src/cli/runtime/serve-supervisor-relocation.test.ts
index 99c36ae8e6b..c642048ccb6 100644
--- a/src/cli/runtime/serve-supervisor-relocation.test.ts
+++ b/src/cli/runtime/serve-supervisor-relocation.test.ts
@@ -89,6 +89,24 @@ describe('relocateServeSupervisor', () => {
     }
   })
 
+  // Why: re-exec from node mode closes the AppImage runtime's keepalive pipe, so the mount is
+  // torn down under the exec and the new image fails to load its libraries (real-host BUG-3).
+  it('stays in place when running from an AppImage, whose files cannot change under it', async () => {
+    const d = deps({
+      env: {
+        ELECTRON_RUN_AS_NODE: '1',
+        APPDIR: resources.replace(/\/Resources$/, ''),
+        APPIMAGE: '/a/Orca.AppImage'
+      }
+    })
+    await expect(relocateServeSupervisor(d)).resolves.toBe('in-place')
+    expect(d.execve).not.toHaveBeenCalled()
+    expect(existsSync(serveSupervisorSnapshotRoot(userData))).toBe(false)
+
+    const elsewhere = deps({ env: { ELECTRON_RUN_AS_NODE: '1', APPDIR: join(root, 'other') } })
+    await expect(relocateServeSupervisor(elsewhere)).resolves.toBe('relocated')
+  })
+
   it('keeps running in place when the copy or the re-exec fails', async () => {
     await writeFile(join(root, 'blocker'), '')
     const blocked = deps({ userDataPath: join(root, 'blocker') })
diff --git a/src/cli/runtime/serve-supervisor-relocation.ts b/src/cli/runtime/serve-supervisor-relocation.ts
index cf68e6b8208..4219c2af743 100644
--- a/src/cli/runtime/serve-supervisor-relocation.ts
+++ b/src/cli/runtime/serve-supervisor-relocation.ts
@@ -7,7 +7,7 @@
 import { createHash } from 'node:crypto'
 import { constants, readFileSync, statSync } from 'node:fs'
 import { cp, mkdir, readdir, rename, rm, stat, writeFile } from 'node:fs/promises'
-import { basename, dirname, join } from 'node:path'
+import { basename, dirname, isAbsolute, join, relative, resolve } from 'node:path'
 import { isProcessAlive } from '../../shared/serve-bundle-coordination'
 
 /** Set on the re-run supervisor: the app root its own `__dirname` no longer points at. */
@@ -132,6 +132,20 @@ async function removeUnusedSnapshots(
   }
 }
 
+/**
+ * An AppImage's files are its own mount (or extracted copy) for the whole run, so no update can
+ * swap them. Re-exec from node mode would also close the runtime's keepalive pipe, which unmounts
+ * the AppImage under the exec and leaves the new image unable to load its libraries.
+ */
+function runsFromAppImage(appRoot: string, env: NodeJS.ProcessEnv): boolean {
+  const appDir = env.APPDIR
+  if (!appDir || !isAbsolute(appDir)) {
+    return false
+  }
+  const inside = relative(resolve(appDir), resolve(appRoot))
+  return inside !== '' && !inside.startsWith('..') && !isAbsolute(inside)
+}
+
 /**
  * Resolves only when the supervisor keeps running from where it is; a successful re-run replaces
  * this process (same pid, so the service manager keeps tracking it) and never returns.
@@ -147,7 +161,8 @@ export async function relocateServeSupervisor(
   if (
     deps.env.ELECTRON_RUN_AS_NODE !== '1' ||
     (typeof override === 'string' && override.trim().length > 0) ||
-    basename(deps.appRoot) !== PACKAGED_APP_ROOT_NAME
+    basename(deps.appRoot) !== PACKAGED_APP_ROOT_NAME ||
+    runsFromAppImage(deps.appRoot, deps.env)
   ) {
     return 'in-place'
   }