Self-updater does not work (AppImage, Linux)

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

self-updater runs, but fails:

➜  ~ zsync2: Using CA bundle found on system: /etc/ssl/certs/ca-certificates.crt
... done!
Starting update...

Updating from generic server via ZSync
zsync2: Using CA bundle found on system: /etc/ssl/certs/ca-certificates.crt
0% done
zsync2: /home/me/Downloads/Cursor-3.7.42-x86_64.AppImage found, using as seed file
zsync2: Target file: /home/me/Downloads/Cursor-3.7.42-x86_64.AppImage
zsync2: Reading seed file: /home/me/Downloads/Cursor-3.7.42-x86_64.AppImage
6.77% done (20.28 of 299.55 MiB)...
zsync2: Usable data from seed files: 6.801763%
zsync2: Renaming temp file
zsync2: Fetching remaining blocks
6.80% done (20.37 of 299.55 MiB)...
zsync2: Downloading from https://downloads.cursor.com/production/2fdd31c9f33f7fbe501f2d57772dc5bf64b63621/linux/x64/Cursor-3.17.8-x86_64.AppImage
zsync2: optimized ranges, old requests count 652, new requests count 17

99.94% done (299.37 of 299.55 MiB)...
zsync2: Verifying downloaded file
100.00% done (299.55 of 299.55 MiB)...
zsync2: checksum matches OK
zsync2: used 21364736 local, fetched 304014528
100.00% done (299.55 of 299.55 MiB)...
Validation error: AppImage no longer comes with signature
Restoring original file
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
[660789:0820/151104.163928:FATAL:content/browser/zygote_host/zygote_host_impl_linux.cc:207] Check failed: . : Invalid argument (22)

note that I am running the appimage with --no-sandbox due to this problem: AppImage run fails without --no-sandbox on Linux

Steps to Reproduce

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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. What you’re seeing is a known issue with the in-app updater for Linux AppImage. It can reject some new builds and restore your original file, which is exactly what the log shows Validation error: AppImage no longer comes with signature → Restoring original file. Your download, disk, and setup are fine. This isn’t something on your side.

For now, the workaround is to update manually. Download the latest AppImage from Cursor · Download and replace your current file with it.

The setuid sandbox error at the end of the log is a separate launch issue from your other thread (168960 AppImage run fails without --no-sandbox on Linux). Let’s keep that discussion there so we don’t mix things up.

I’ve shared this with the team and we’re tracking it. There’s no timeline yet, but I’ll post here when there’s an update.