[BUG] Cross-platform sync failure (Desktop/Web/Android) causing Cowork conversations and chats to disappear — suspected server-side incident

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?

There is a synchronization failure between Claude Desktop, Claude Web (claude.ai), and the Claude Android app that has resulted in Cowork conversations and some regular chats disappearing entirely.

Timeline:

A few days before July 26, 2026: I noticed the web app was consistently lagging behind Desktop and Android — conversations and updates made on Desktop/Android weren't reflecting on Web in real time. I reported this directly to Fin (AI support agent) at the time. Since Desktop and Android still seemed to work and stay in sync with each other, I continued working normally on those two surfaces.
July 26, 2026: The issue escalated. Multiple Cowork conversations, and some regular chats, disappeared from the sidebar entirely — not archived, not deleted by me. This is visible across devices (same account, different machines), which points to a server-side sync/storage issue rather than a local cache problem on one device.

Mobile app status: As of now, the Cowork conversations still appear on the Android app — though I'm not fully certain all of them are present (I haven't cross-checked the full list against what was previously visible on Desktop/Web).

I have not tested iOS or macOS, only Windows Desktop, Web, and Android.

Operating System

Windows (Desktop), Android (mobile), Web (browser — OS not applicable)

What Should Happen?

Desktop, Web, and Android should stay consistently synchronized for Cowork conversations and chats, with no silent data loss. If a sync delay occurs, it should not result in permanent, cross-device disappearance of conversation history.

Error Messages/Logs

No error dialog was shown when conversations disappeared. Separately, attempting to reach human support through the in-app Cowork contact screen shows a blank white page.

**Local folder access failure from mobile — technical detail:**

My Cowork conversations were configured with access to a local folder on my Windows PC (used to periodically save deliverables and markdown files). Attempting to use that local-file access from within a Cowork conversation on the Android app fails, with three distinct errors observed:

Tool: mcp__remote-devices__device_list_dir
Input: { "path": "C:\Users\<redacted>\<Folder1>\<Folder2>\<Folder3>\<Project Folder>" }
Error: No such tool available: mcp__remote-devices__device_list_dir
Tool: mcp__remote-devices__device_commit_files
Input: { "files": [{"fileUuid": "3467b48b-7b51-4e54-8dbb-2d9b1c933852", "devicePath": "C:\\Users\\<redacted>\\<Folder1>\\<Folder2>\\<Folder3>\\<Project Folder>\\<file>.md"}] }
Error: No such tool available: mcp__remote-devices__device_commit_files
Tool: mcp__remote-devices__get_device_info
Error: The device this session is bound to is not connected to the bridge.

This points to a broken device bridge between the mobile app and the Desktop app: the mobile Cowork session appears to reference a device/session binding whose local-file MCP tools (mcp__remote-devices__*) are either unregistered or unreachable, even though (per Anthropic's own documentation) local file access should work through the Desktop app when it's open and connected. Given the timing, this looks related to the same sync breakdown described above rather than a separate issue.

Steps to Reproduce

Not reliably reproducible on demand. Observed sequence:

Use Cowork/chat across Desktop, Web, and Android on the same account, with a local folder connected via Desktop.
Notice Web lagging behind Desktop/Android for some period.
Continue using Desktop and Android normally.
At some point (in my case, July 26, 2026), Cowork conversations and some chats disappear from the sidebar across all devices.
From Android, attempt to access/save to the previously connected local folder — fails with the errors above.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

N/A — issue appears server-side, not tied to a specific client version

Claude Code Version

N/A — Claude Desktop (Cowork), Claude Web, Claude Android

Platform

Other

Operating System

Windows

Terminal/Shell

Other

Additional Information

I believe this is a server-side sync incident affecting multiple accounts, not an isolated case — I did not archive, delete, or otherwise trigger removal of any conversation. Supporting evidence:

Anthropic's status page (status.claude.com) confirms two incidents on July 26 (09:17 UTC) and July 27 (08:16 UTC), both explicitly listing Claude Cowork as an affected service, though neither incident description mentions conversation/session loss specifically.
Related reports already on this tracker describing the same disappearance pattern: #59850, #54113, #22931, #60669.
I could not reach human support through the in-app contact screen (blank page) and had to go through Fin on support.claude.com, which initially gave inaccurate information before correcting itself, and confirmed no live human escalation is available through that channel — only an eventual email follow-up with no ticket number.

If you're experiencing this too, please comment below with:

Which surfaces you use (Desktop / Web / iOS / Android / macOS) and which OS/versions
Your plan (Free / Pro / Max / Team / Enterprise)
Roughly when you first noticed sync lag, and when (if applicable) conversations actually disappeared
Whether it affected Cowork conversations, regular chats, or both
Whether you've had contact with support/Fin about it, and what response you got

The more independent reports with dates/times, the easier it'll be for Anthropic to correlate this with a specific backend incident.