[BUG]

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

subject: Re: Conversation ID 215474356405859 — Cowork broken only on my Max account; new $20 Pro account works fine on same machine
Hi,
I need a human agent to read this in full. Fin has now deflected me five times. Conversation ID for reference: 215474356405859.
The definitive proof this is an account-level backend issue:
I just created a brand-new account with a different email and paid $20 for Claude Pro. Cowork works perfectly on that account, on the exact same Windows machine, with the exact same Claude desktop app installation. Then I switch back to my Max account and Cowork throws spawn ENAMETOOLONG on every chat immediately.
Same computer. Same app. Same network. Same Windows install. The only variable is which account is signed in. This is not a Windows bug, not an app bug, not a Cowork bug — it is something broken on my Max account specifically.
Full background — what's been tried and what's been confirmed:
The original issue: spawn ENAMETOOLONG on every Cowork chat (new, old, empty) on my Max account.
Local diagnostics already completed:

Windows 11 25H2, build 26200.8457 (stable GA, not Insider)
Claude desktop app version 1.7196.1.0, MSIX install at C:\Program Files\WindowsApps\Claude_1.7196.1.0_x64__pzs8sxrjxfjjc
PATH length: 848 characters
AppData, LocalAppData, UserProfile all on local C: drive, no redirection
Full clean reinstall completed: uninstalled → rebooted → deleted %APPDATA%\Claude, %LOCALAPPDATA%\Claude, %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc → reinstalled from claude.com/download
Cowork still broken on Max account after every single one of these steps

Cross-machine reproduction:

Same ENAMETOOLONG error on a completely different second computer signed into the same Max account
On the second computer, my conversations, projects, and memory are also missing despite signing into the correct account with the correct email

Cross-account reproduction (new, today):

Created new account, paid $20 for Pro on a separate email
Signed into Pro account on the same machine that fails for my Max account
Cowork works perfectly on the Pro account, instantly
Switched back to Max account, same machine, same install — ENAMETOOLONG immediately

Possibly related, from DevTools console (Max account only):

Repeated 404s on /api/organizations/<uuid>/model_configs/claude-opus-4-7[1m] — note the square brackets in the model ID, which looks malformed and may be what's pushing the subprocess command past Windows' length limit
MaxListenersExceededWarning on AutoUpdater state in the IPC layer

Support history on this case:

Case has been closed as "resolved" twice without anyone verifying on my account
Fin has acknowledged in writing — twice — that this is "an account-specific backend issue requiring engineering investigation"
Fin has now also acknowledged it cannot assign cases to humans
Five separate Fin replies have all deflected me back to self-serve options instead of routing to a human
Two Opus 4.7 incidents resolved on May 18 and May 19 — neither fixed my account
The Intercom support chat widget itself was throwing JavaScript errors when I tried to use it

What I am asking for:

Assign this case to a human agent. Please confirm by email when this has happened.
Have engineering investigate why Cowork fails on my Max account but works on a brand-new Pro account on the same machine. The bad model config URL with the bracketed [1m] suffix is a strong starting point.
Service credit for the Max plan downtime. I have been paying $200/month for a plan whose flagship feature has been broken on my account for days, while a $20 Pro account on the same machine works instantly.
If this cannot be resolved in a reasonable timeframe, I will downgrade my Max plan, keep using the working Pro account, and dispute the most recent $200 charge with my card issuer as service not rendered.

I have done everything reasonable as a customer. This needs an engineer, not another AI deflection.
— Hasan

What Should Happen?

Cowork should open and accept chats normally on my Max account, the same way it does on a fresh Pro account on the same machine with the same Claude desktop app install.

Error Messages/Logs

spawn ENAMETOOLONG — thrown on every Cowork chat (new, old, empty) on my Max account only.
DevTools console also shows repeated 404s on:
/api/organizations/<uuid>/model_configs/claude-opus-4-7[1m]
Note the square brackets in the model identifier — this looks malformed and may be what's pushing the spawned subprocess command past Windows' command-line length limit.
Also: MaxListenersExceededWarning on AutoUpdater_$_updaterState_$store$_update in the IPC layer (listener leak).
Anthropic Support Conversation ID: 215474356405859

Steps to Reproduce

Sign into Claude desktop app v1.7196.1.0 on Windows 11 25H2 (build 26200.8457) with my Max account
Open Cowork
Start any chat — new, existing, or empty
spawn ENAMETOOLONG is thrown immediately

Cross-checks proving this is account-specific, not local:

Reproduces on a second, completely different Windows computer signed into the same Max account
On a brand-new Pro account ($20/month) signed in on the same machine with the same app install, Cowork works perfectly and immediately
Switching back to the Max account on the same machine reproduces the error instantly

Local troubleshooting already completed (none resolved it):

Full uninstall, reboot, deleted %APPDATA%\Claude, %LOCALAPPDATA%\Claude, %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc, reinstalled from claude.com/download
Verified PATH length 848 chars, AppData/LocalAppData/UserProfile all on local C:, no redirection
Verified not on Windows Insider channel

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

N/A

Claude Code Version

N/A — this is a Claude Desktop (MSIX) bug, not Claude Code CLI. Filing here because previous Cowork desktop bugs have been filed in this repo (see issues #55879, #51143, #49551, #36157). Claude desktop app version: 1.7196.1.0

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

Account-level backend issue, not local: Bug reproduces across two different computers on my Max account, but does NOT reproduce on a brand-new Pro account signed in on the same machine with the same app install. The only variable that changes the outcome is which account is signed in.
Possible root cause: The 404 endpoint /model_configs/claude-opus-4-7[1m] contains square brackets in the model identifier. If the desktop app is constructing the Cowork subprocess command using this malformed model string, that could push the spawned command past Windows' ~8,191 character CreateProcess limit, producing ENAMETOOLONG regardless of chat content. This would also explain why empty new chats fail and why a Pro account (presumably routed to a different model config) is unaffected.
Also affected for this account: Conversations, projects, and memory do not appear when signing into the Max account on a second computer — confirmed correct email/account.
Support history: Anthropic support has closed this case as "resolved" twice without verifying on my account. Fin (AI agent) has acknowledged in writing — twice — that this is "an account-specific backend issue requiring engineering investigation," but cannot route to a human agent. Conversation ID: 215474356405859.