Desktop UI crashes on load with Cannot read properties of undefined (reading 'id') in session bundle

Summary

I hit the same crash twice today on OpenCode Desktop/Web UI startup. The app shows the black "Something went wrong" screen before the main UI finishes loading.

Version

OpenCode: 1.2.20

Actual Behavior

The app crashes during load with:

TypeError: Cannot read properties of undefined (reading id)
    at Object.fn (http://127.0.0.1:4096/assets/session-CiCXhYTR.js:14:79062)
    at Mk (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:6835)
    at Pl (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:6592)
    at op (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:8002)
    at D6 (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:8883)
    at pL (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:8255)
    at qr (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:8187)
    at http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:5043

The crash screen text is:

Something went wrong
An error occurred while loading the application.

Expected Behavior

If session data is missing or malformed, the app should handle it gracefully instead of crashing the entire UI during startup.

Frequency

Happened twice today

Notes

This looks related to session bootstrap/rendering because the top frame is in assets/session-*.js.
There is already #11702 about runtime crashes from unsafe assumptions, but this report is a user-facing UI crash on 1.2.20 with a concrete startup stack trace.
I have a screenshot of the error screen and can add it in a follow-up comment if that helps.

TypeError: Cannot read properties of undefined (reading 'state')
    at c (http://127.0.0.1:4096/assets/session-CiCXkYTR.js:14:76803)
    at get metadata (http://127.0.0.1:4096/assets/session-CiCXkYTR.js:14:77783)
    at s (http://127.0.0.1:4096/assets/session-CiCXkYTR.js:14:83444)
    at Object.fn (http://127.0.0.1:4096/assets/session-CiCXkYTR.js:14:83669)
    at Mk (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:6835)
    at Pl (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:6592)
    at op (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:8002)
    at D6 (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:8883)
    at pL (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:8255)
    at qr (http://127.0.0.1:4096/assets/index-jLZvC0f3.js:2:8187)

just happened to me on the web UI, but if I quickly change to a different project as soon as it starts everything is fine. Maybe has something to do with what I was working before restarting the PC

screenshot of working just fine on a random project I didnt even open yesterday

what happens when going to my most recent project

TypeError: Cannot read properties of undefined (reading 'length')
    at Object.fn (http://127.0.0.1:4096/assets/session-Cg8YeoLd.js:14:50663)
    at Mk (http://127.0.0.1:4096/assets/index-Dl3PGFdp.js:2:6835)
    at Pl (http://127.0.0.1:4096/assets/index-Dl3PGFdp.js:2:6592)
    at Object._6 (http://127.0.0.1:4096/assets/index-Dl3PGFdp.js:2:5606)
    at get style (http://127.0.0.1:4096/assets/session-Cg8YeoLd.js:14:51075)
    at jL (http://127.0.0.1:4096/assets/index-Dl3PGFdp.js:2:24146)
    at Object.fn (http://127.0.0.1:4096/assets/index-Dl3PGFdp.js:2:23793)
    at Mk (http://127.0.0.1:4096/assets/index-Dl3PGFdp.js:2:6835)
    at Pl (http://127.0.0.1:4096/assets/index-Dl3PGFdp.js:2:6592)
    at Oe (http://127.0.0.1:4096/assets/index-Dl3PGFdp.js:2:1831)

my setup

          ▗▄▄▄       ▗▄▄▄▄    ▄▄▄▖             pollito@Lenovo-ideapad-L340-15IRH
          ▜███▙       ▜███▙  ▟███▛             ---------------------------------
           ▜███▙       ▜███▙▟███▛              OS: NixOS 25.11 (Xantusia) x86_64
            ▜███▙       ▜██████▛               Host: 81LK (IdeaPad L340-15IRH G)
     ▟█████████████████▙ ▜████▛     ▟▙         Kernel: Linux 6.12.62
    ▟███████████████████▙ ▜███▙    ▟██▙        Uptime: 4 mins
           ▄▄▄▄▖           ▜███▙  ▟███▛        Packages: 1998 (nix-system), 128)
          ▟███▛             ▜██▛ ▟███▛         Shell: zsh 5.9
         ▟███▛               ▜▛ ▟███▛          Display (BOE0700): 1920x1080 @ 1]
▟███████████▛                  ▟██████████▙    DE: Cinnamon 6.4.13
▜██████████▛                  ▟███████████▛    WM: Muffin (X11)
      ▟███▛ ▟▙               ▟███▛             WM Theme: Adapta-Nokto (Mint-Y)
     ▟███▛ ▟██▙             ▟███▛              Theme: Mint-Y-Dark-Aqua [GTK2/3/]
    ▟███▛  ▜███▙           ▝▀▀▀▀               Icons: Mint-Y-Aqua [GTK2/3/4]
    ▜██▛    ▜███▙ ▜██████████████████▛         Font: JetBrainsMono Nerd Font (1]
     ▜▛     ▟████▙ ▜████████████████▛          Cursor: Bibata-Modern-Classic (2)
           ▟██████▙       ▜███▙                Terminal: alacritty 0.16.1
          ▟███▛▜███▙       ▜███▙               Terminal Font: JetBrainsMono Ner)
         ▟███▛  ▜███▙       ▜███▙              CPU: Intel(R) Core(TM) i7-9750H z
         ▝▀▀▀    ▀▀▀▀▘       ▀▀▀▘              GPU 1: NVIDIA GeForce GTX 1650 M]
                                               GPU 2: Intel UHD Graphics 630 @ ]
                                               Memory: 1.52 GiB / 15.49 GiB (10)
                                               Swap: 0 B / 24.78 GiB (0%)
                                               Disk (/): 159.02 GiB / 450.62 Gi4

I have multiple different servers on different ubuntu VMs that are all doing this today. Switching the hostname that I use to access the application appears to fix it, until I open up the project.

~~This is happening for me but I have not updated opencode (currently on 1.2.15) so it is slightly odd~~ opencode web is auto updating and running 1.2.20

This is happening for me, on 1.2.19 and 1.2.20. Same error output

guys have you used gpt 5.4 model? i got the same err

I uninstalled and reinstalled opencode, and it continues happening as soon as I begin a new session in the web ui. I wonder if there isn't some aggressive time-change stuff going on in there.

guys have you used gpt 5.4 model? i got the same err

I use.

Same issue here, updated to the latest version 1.2.25 still not resolving it.

Root Cause Analysis

The crash originates in packages/app/src/components/session/session-header.tsx at line 306:

const current = createMemo(() => options().find((o) => o.id === prefs.app) ?? options()[0])

current() returns undefined when options() is temporarily empty — which happens during startup before the file-manager/app list resolves, or during project switching. Downstream accesses like current().id, current().label, and current().icon (lines 421, 423, 428, 458) then throw the TypeError.

Fix

Add a hardcoded fallback so current() is never undefined:

const current = createMemo(
  () => options().find((o) => o.id === prefs.app) ?? options()[0] ?? { id: "finder", label: "Finder", icon: "finder" } as const
)

This is the same defensive pattern used in PR #16476 (props.text?.length ?? 0) and PR #16475 (createMemo(() => props.text ?? "")) which fix the structurally identical Cannot read properties of undefined (reading 'length') crash in TextShimmer (issue #16473).

fix(app): session-header crashes when switching projects #16467 — same current() undefined crash, triggered by fast project switching
bug(desktop): "Stale read from <Show>" crash when running multiple agents — v1.2.20 #16323 — broader <Show> stale-read analysis; session-header.tsx is listed as one of the unfixed files
TypeError in Web UI - Cannot read properties of undefined (reading 'length') #16473 / PR fix(app): text-shimmer undefined length #16475 / PR fix(ui): guard TextShimmer against undefined text prop #16476 — identical pattern in TextShimmer

A PR fixing this is incoming.

fix(app): guard session-header current() against undefined when optio…

am i correct in understanding that when you run opencode web most requests for static assets are forwarded to app.opencode.ai and therefore we have no way to control which version of opencode desktop is running via the web command?

https://github.com/anomalyco/opencode/blob/dev/packages/opencode/src/server/server.ts#L564-L579

@tobeycodes

@tobeycodes Yes, that's correct — with one important nuance.

When you run opencode web, the server starts locally but the UI assets (HTML/JS/CSS) are proxied live from https://app.opencode.ai via the catch-all route in server.ts:564-579. So the frontend version you get is whatever is currently deployed to app.opencode.ai, not the version that matches your local opencode binary.

This means:

You can't pin the UI version by staying on an older opencode binary — the frontend always comes from the live CDN
Fixes deployed to app.opencode.ai will reach you immediately without a binary update
The crash in this issue will be resolved once PR #16478 (or a similar fix) is merged and deployed to app.opencode.ai

The Desktop app (Tauri) is different — it bundles the UI assets locally, so the version is pinned to the release you installed.

@tobeycodes Yes, that's correct — with one important nuance.

where is the nuance? all you did was confirm what i said

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Desktop UI crashes on load with `Cannot read properties of undefined (reading 'id')` in session bundle #16459

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Desktop UI crashes on load with Cannot read properties of undefined (reading 'id') in session bundle #16459

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Summary

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cyberprophet commented on Mar 7, 2026

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cyberprophet commented on Mar 7, 2026

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tobeycodes commented on Mar 7, 2026

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tobeycodes commented on Mar 7, 2026

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Desktop UI crashes on load with `Cannot read properties of undefined (reading 'id')` in session bundle #16459