AppImage run fails without --no-sandbox on Linux

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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

➜  ~ ~/Downloads/Cursor-3.7.42-x86_64.AppImage
The setuid sandbox is not running as root. Common causes:
  * An unprivileged process using ptrace on it, like a debugger.
  * A parent process set prctl(PR_SET_NO_NEW_PRIVS, ...)
Failed to move to new namespace: PID namespaces supported, Network namespace supported, but failed: errno = Operation not permitted
[666572:0820/151432.372846:FATAL:content/browser/zygote_host/zygote_host_impl_linux.cc:207] Check failed: . : Invalid argument (22)
[1]    666572 trace trap (core dumped)  ~/Downloads/Cursor-3.7.42-x86_64.AppImage

Steps to Reproduce

Run the appimage distribution on ubuntu

Expected Behavior

.

Operating System

Linux

Version Information

Version: 3.15.6
VS Code Extension API: 1.128.0
Commit: a1f686545fd0ce8917bbd2449f733551a9bce420
Date: 2026-08-06T01:41:03.876Z
Layout: IDE
Build Type: Stable
Release Track: Default
Electron: 40.10.3
Chromium: 144.0.7559.236
Node.js: 24.15.0
V8: 14.4.258.32-electron.0
xterm.js: 6.1.0-beta.291
OS: Linux x64 6.8.0-106-generic

Does this stop you from using Cursor

No - Cursor works, but with this issue

5

Hey, thanks for the detailed report. This is a known issue we’re tracking. Newer Ubuntu releases 24.04+ restrict unprivileged user namespaces by default, and the AppImage FUSE mount is nosuid. As a result, both Chromium sandbox options aren’t available, so the process crashes on startup.

Options until we have a proper fix:

  • Install Cursor from the .deb package instead of the AppImage. It integrates with the system and the sandbox works normally.
  • Allow user namespaces: sudo sysctl kernel.apparmor_restrict_unprivileged_userns=0 (note this lowers overall system security).
  • Keep launching with --no-sandbox, like you’re doing now.

I can’t share an ETA yet, but I’ll post in the thread when there’s an update.