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

[HSBE31]

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?

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.

[samueldcorbin]

I am also experiencing this.

Messages on Android do not appear in web, even with forced refreshes and Chrome restart. If I sent a message on web, it silently forks the conversation and the Android conversational turns are lost (on both web and Android).
Max plan.
Noticed yesterday.
Regular chat, not Cowork.
No contact with support.

[Ed-Marsh]

Surfaces: Windows Desktop app, Web (claude.ai), Android
Plan: Pro
Timeline: Cross-surface sync worked for weeks. Around Aug 3, 2026, one-way failure began: sessions started on Desktop no longer appear on Web or Android. The reverse still works — sessions started on phone/web appear on Desktop normally.
Affected: Cowork sessions and chats started on Desktop.
Support contact: Spent ~4 hours troubleshooting via Claude, including an advised uninstall/reinstall of the Desktop app, which deleted my local session history without resolving the sync issue. Flagging so others don't reinstall — it doesn't help and destroys local data.
Notes: Timing is shortly after the July 26–27 incidents that listed Claude Cowork as affected.

Update (Aug 10): Isolated the variable further — regular Chat sessions are propagating correctly across surfaces (tested live, multiple round-trips, synced within seconds). A Cowork session started immediately afterward has not appeared on other surfaces at all. This suggests the failure may be specific to Cowork's sync/storage path rather than a general surface-to-surface sync issue — worth checking whether Cowork sessions use a different backend sync mechanism than standard chats.

[Zooarcher]

Corroborating on Windows desktop, Max plan, ongoing as of August 2026.
This issue is one instance of a systemic pattern I have documented across
eleven defects, validated against the official documentation and this
tracker, published here: https://gist.github.com/53f85e6d48eaec4a661209fcf3f49ae6.git.
This issue corresponds to Defect 11 in that report. The pattern ties together stale persisted state, broken
session isolation, unenforced controls, and update regressions; treating
these as isolated symptoms is why they keep recurring.

[Weisbergd]

Chat pin/rename state and other chat information not syncing across devices,

I'm experiencing a cross-device sync failure with claude.ai. I pinned a chat and renamed it on one device, but neither the pin status nor the new title appears on my other device(s) — the chat still shows its old name and is not pinned. Sometimes chats themselves are not synced.

This matches a known issue reported on GitHub (anthropics/claude-code #81658), which describes a synchronization failure between Claude Desktop, Web, and the Android app where conversations and metadata updates lag or fail to propagate across devices on the same account, pointing to a server-side sync/storage issue rather than a local cache problem.

Devices affected: Mac desktop app, iPhone app, iPad app

[PaulArvada]

I have the same problem. I am using MacOS claud app. some of the older chats still sync. If I add to the chat on my Mac, I see it on my other devices. if an add to the same chat on my other devices, I see it on the Mac. These are all older chats. But any of the recent chats created on the Mac are orphaned. I do not see them in claude.ai or on any of my other devices. I would say this is a significant problem

[fontiela]

I have the same problem, I'm using several devices based on MacOS and iOS and conversations aren't sync cross-platforms. Claude Pro plan

[hudhomer-cyber]

I'm experiencing the exact same issue as described here.

My case:

• Date first noticed: August 13, 2026
• Devices affected: Desktop (Windows), Phone (can access files via OneDrive but Cowork chat/project not visible)
• Status: My active Cowork session with Weight Tracker project doesn't appear on mobile, even though I can edit the file directly
• Support: I submitted a report through Cowork's support channel and was ignored
• Current impact: Cannot access my chat history or project on mobile; works normally on desktop

This appears to be the mobile sync issue described in the main report. Adding my case to the evidence pile.

[kwpropertiesinvest-ui]

experiencing same issue