[BUG] Claude Desktop blank screen on Windows + Cowork unusable + sandbox API errors — Max subscriber, 9-day outage

[wilkinsonjames1991-gif]

Preflight Checklist

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

What's Wrong?

Same issue as #51143, #49551, #36157, #26921, #26302.

Platform: Claude Desktop, Microsoft Store version, Windows 11
Subscription: Claude Max
Feature affected: Cowork

Symptoms:

• Desktop app launches to blank/white screen, repeatedly (3+ times in one morning)
• Cowork sandbox API Error 400: "Could not process image" persists across sessions
• Issue only occurs when accessing Cowork — regular Claude desktop and claude.ai browser work fine

Timeline:

• April 24, 2026: Lost a full week of Cowork projects and scheduled tasks during Windows reinstall (data wipe, no recovery path)
• May 2, 2026: Cowork sandbox outage confirmed by another user, persistent API errors, desktop app freezing/blank screen
• May 3, 2026: Issues continuing despite full PC reboot, Repair via Settings, latest version confirmed

Request IDs:

• req_011CafVmH2orsnrr4YCK1pMd
• req_011CafW4EUk7kB7yxgQTpceS
• req_011CafWmbp2iCDWA5ZdhJgQB

Support response: AI agent (Fin) refused human escalation in writing and refused refund. Conversation ID: 215474162478297

Business impact: Small business owner (JCS Tree Care Professionals), 9 days of lost productivity on a paid Max plan.

This is at minimum the 6th similar Cowork stability bug filed in 2026. Requesting engineering acknowledgment that Cowork on Windows desktop has known stability issues affecting paid Max subscribers.

What Should Happen?

Claude Desktop should launch and render the UI normally on Windows 11. Cowork should be accessible and stable for Max subscribers without sandbox API errors or blank screen freezes.

Error Messages/Logs

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"Could not process image"}}

Request IDs:
- req_011CafVmH2orsnrr4YCK1pMd
- req_011CafW4EUk7kB7yxgQTpceS
- req_011CafWmbp2iCDWA5ZdhJgQB

Conversation ID (Anthropic Support): 215474162478297

Error persists across multiple Cowork sessions. Sandbox reported down by another user May 2 evening. Desktop app continues to go blank/freeze repeatedly even after sandbox came back online.

Steps to Reproduce

1. Open Claude Desktop (Microsoft Store version) on Windows 11
2. Sign in as Claude Max subscriber
3. Click into a Cowork project
4. App freezes within seconds — screen goes blank/white
5. Force quit via Task Manager (multiple "Claude" processes must be killed)
6. Relaunch app
7. Same blank screen occurs again

Additional reproduction:

• API Error 400 "Could not process image" appears in Cowork conversations and persists across sessions, suggesting corrupted image in conversation history that re-fails on every new message
• Issue occurs only with Cowork; regular Claude Desktop chat and claude.ai browser work fine
• Repair via Settings > Apps > Advanced Options did not resolve
• Full PC reboot did not resolve
• Latest Microsoft Store version installed and confirmed

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Cowork was working April 23, 2026 (day before April 24 data loss event)

Claude Code Version

N/A — Issue is in Claude Desktop (Microsoft Store version) for Windows, not Claude Code CLI. This bug report is being filed here because issues #51143, #49551, #36157, and #26921 documenting the same Cowork desktop app bug were filed in this repo.

Platform

Other

Operating System

Windows

Terminal/Shell

Other

Additional Information

Related GitHub Issues (same Cowork stability bug):

• [BUG] Claude Desktop persistent blank/white screen on Windows — Cowork unusable, multiple reinstalls have no effect #51143 — Persistent blank/white screen on Windows, Cowork unusable
• Claude Desktop goes blank on Windows, requires Task Manager to kill all processes before app can reopen #49551 — Claude Desktop goes blank on Windows, Task Manager required
• [Cowork] Dispatch causes black screen freeze, requires full data wipe to recover #36157 — Cowork Dispatch causes black screen freeze, requires data wipe
• [BUG] Cowork UI freezes mid-response; other chat threads go blank until app restart (macOS) #26921 — Cowork UI freezes mid-response, other threads go blank
• [BUG] Claude Desktop 1.1.3189 severe UI lag and mouse stutter on Windows — performance regression after update #26302 — Cowork VM performance regression after update

Anthropic Support response:

• Refused human escalation in writing
• Refused refund despite 9-day outage on paid Max plan
• Documented data loss April 24 with no recovery path
• Conversation ID: 215474162478297

Why this matters:
This is at minimum the 6th similar Cowork stability report. Multiple reports have been auto-tagged "invalid" or "stale" and closed without engineering response. As a paid Max subscriber running a small business on Cowork, I am requesting acknowledgment that Cowork on Windows desktop is a known issue with active engineering ownership.

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] Claude Desktop persistent blank/white screen on Windows — Cowork unusable, multiple reinstalls have no effect #51143
2. Claude Desktop goes blank on Windows, requires Task Manager to kill all processes before app can reopen #49551
3. [BUG] Claude Cowork constantly crashing after Teams moved from Chat to Cowork #55487

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
• To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

[wilkinsonjames1991-gif]

Not closing as duplicate. Adding context that the linked issues lack:

1. Paid Max subscriber business impact — 9-day outage on a paid plan is materially different from the existing Pro/free user reports
2. Documented data loss event (April 24, 2026) — No recovery path was provided. Anthropic Support confirmed local-only storage with no cloud backup for Cowork projects
3. Support refused human escalation in writing — Conversation ID 215474162478297 documents Anthropic's AI agent (Fin) refusing both refund AND human supervisor escalation for a paying business customer
4. Pattern with [BUG] Claude Desktop persistent blank/white screen on Windows — Cowork unusable, multiple reinstalls have no effect #51143 and Claude Desktop goes blank on Windows, requires Task Manager to kill all processes before app can reopen #49551 confirms recurring issue — When an automated bot identifies duplicates, that itself is evidence engineering has not addressed the root cause across multiple reports

Requesting this issue remain open until engineering provides:

• Acknowledgment of Cowork Windows desktop stability problem
• Timeline for fix
• Documented backup procedure for Max subscribers using Cowork for business operations

@anthropics/claude-code-team please review.

[SYL-322]

Same bug

[wilkinsonjames1991-gif]

Thanks for confirming. Can you share:
OS / Claude Desktop version
Subscription tier (Free/Pro/Max)
When the issue started for you

Building a pattern across affected users to push for engineering response.

[wilkinsonjames1991-gif]

The core problem stated plainly:

Cowork's product promise is "AI runs your tasks while you do other things." When the app cannot remain running — through blank screens, sandbox outages, or API errors — the entire product premise fails.

This is not a minor bug. It is a fundamental contradiction between what Cowork is sold as and how it actually performs on Windows for paid Max subscribers.

Either Cowork is production-ready for business use (and these stability issues require urgent engineering ownership), or it is beta software that should be labeled as such with appropriate refund policies for affected paying customers.

[SYL-322]

Thanks for confirming. Can you share: OS / Claude Desktop version Subscription tier (Free/Pro/Max) When the issue started for you

Building a pattern across affected users to push for engineering response.

Windows, Claude 1.5354.0 (9a9e3d), Max
I just switched from Mac to Windows, so I’m not sure when this issue started.

[wilkinsonjames1991-gif]

Thanks. That's a clear pattern emerging:

• Both Max subscribers
• Both Windows
• Latest Claude Desktop version (1.5354.0)
• Same Cowork blank-screen / instability bug

Combined with prior reports #51143 (Pro/Windows), #49551 (Windows), #36157 (Cowork freeze), #26921 (Cowork UI freeze), and #26302 (Cowork VM regression), this is now 6+ documented reports of Cowork instability on Windows desktop spanning multiple subscription tiers and months.

@anthropics please confirm whether this is in active engineering triage. Auto-tagging duplicates without resolution is not a fix.