Troubleshooting
Claude Cowork Not Working? Start Here
Cowork stuck, won't open, or just not doing anything useful? This triage guide covers the top six failure modes and walks you to the right fix fast.
Quickest fix: Check that you are on a paid Claude plan (Pro or Max), that Cowork is toggled on in settings, and that your app is up to date. These three things account for the majority of 'nothing works' reports.
Cowork is not working. Something is wrong and you are not sure what. The error message, if there is one, is vague. You have poked at settings and nothing obvious stands out. You just want to know what to try first.
This is that page.
Claude Cowork has several distinct failure modes, and they look similar from the outside but have very different fixes. This guide walks you through a triage sequence to figure out which failure mode you are in, then points you to the right detailed fix.
Universal First Aid: Check These Before Anything Else
Eighty percent of “Cowork not working” reports trace back to one of these four things. Check them first because they take two minutes and rule out the boring causes before you dig into anything complicated.
1. Are you on a paid plan?
Cowork requires a Claude Pro or Max subscription. It does not work on the free tier. Go to https://claude.ai, open your account settings, and confirm your plan. If you recently changed plans or your payment failed, Cowork access may have lapsed.
2. Is Cowork enabled in settings?
Open the Claude desktop app, go to Settings, and find the Cowork or Agent section. There should be a toggle. Make sure it is on. If you do not see the section at all, your plan may not include Cowork, or you may be looking at an older app version that predates the feature.
3. Is the app up to date?
Anthropic ships fixes for Cowork regularly. An outdated build may have bugs that were patched weeks ago. Open the app menu, check for updates, and install them. Then relaunch and try again.
4. Is Anthropic having a service incident?
Check https://status.anthropic.com. If there is an active incident affecting the Claude API or the desktop app, nothing you do locally will fix it. Wait for the incident to resolve and try again.
If all four of those check out and Cowork is still broken, read on.
Triage Flowchart: Finding Your Failure Mode
Work through these in order. Each section describes the symptoms and links to the detailed fix guide.
Failure Mode 1: The Workspace Will Not Start
Symptoms: You see “failed to start workspace,” “workspace still starting,” or “cannot connect to Claude API” when you try to use Cowork’s tools. The app opens but the agent cannot do anything because the sandbox environment never boots.
What is happening: Cowork runs tools inside a sandboxed Linux environment that has to start up before the agent can use them. If the sandbox fails to boot, or if the app cannot reach the Claude API over the internet, you get this error.
Common causes: The workspace is still booting and you need to wait and retry. Your internet connection dropped or is being filtered by a VPN or corporate proxy. Your disk is too full to hold the sandbox image. On Windows specifically, VPN software frequently blocks the local socket the workspace uses.
Go here: Failed to Start Workspace
Failure Mode 2: Permission Denied When Accessing Files or Folders
Symptoms: Cowork says it cannot access a file or folder you want it to work with. It may say “permission denied,” “access not granted,” or refuse to read a particular path. It can open the app fine and the workspace starts, but it cannot touch the files you need.
What is happening: Cowork asks for explicit permission to access each folder you want it to work in. On macOS, this is enforced by the operating system. If you have not granted access, or if you revoked it, the agent is genuinely blocked at the system level.
Common causes: You never granted folder access for that directory. You moved the folder to a new path after granting access. macOS privacy settings were reset by an OS update.
Go here: Permission Denied
Failure Mode 3: Context Window Exceeded
Symptoms: Cowork stops mid-task, says the context is too large, or produces an error about token limits. Long conversations or tasks involving large files are especially prone to this.
What is happening: Every conversation with Claude has a context window, which is a limit on how much text (your messages, the agent’s responses, file contents, tool results) can be in memory at once. When you exceed it, the conversation cannot continue in its current form.
Common causes: A very long conversation that accumulated a lot of back-and-forth. A task that read in many large files at once. An agent that repeated itself many times before getting stuck.
Go here: Context Window Exceeded
Failure Mode 4: MCP Server Connection Failed
Symptoms: A specific tool or integration is not working, even though the rest of Cowork seems fine. You might see “MCP connection failed,” a tool returning errors, or an integration (like a connected app or data source) that is not responding.
What is happening: Cowork extends its capabilities through MCP (Model Context Protocol) servers, which are local or remote services that provide tools. If one of these servers fails to start or loses its connection, the tools it provides stop working.
Common causes: The MCP server process crashed or was not running when Cowork started. A configuration change broke the server’s startup command. A network-connected MCP server is unreachable.
Go here: MCP Connection Failed
Failure Mode 5: Sub-Agents Time Out or Never Finish
Symptoms: You gave Cowork a large multi-part task, it started spawning parallel agents to work on it, and now the spinner keeps going without any progress. It has been five or ten minutes and nothing is finishing.
What is happening: Cowork can split big jobs into parallel sub-agents that work simultaneously. If one of those agents gets stuck (waiting on a slow tool, caught in a reasoning loop, or blocked by a resource another agent is using), the coordinator waits indefinitely for it to report back.
Common causes: Too many parallel sub-agents running at once. A sub-agent waiting on a tool call that never returns. A task that is too large for a single agent to handle within its context limits.
Go here: Sub-Agent Timeout
Failure Mode 6: Cowork is Available on Your Plan but You Do Not See It
Symptoms: You have a paid Claude plan, the app is up to date, but you cannot find the Cowork toggle or the agentic features just do not appear. Everything looks like the regular Claude chat.
What is happening: Cowork is rolling out gradually, and availability can depend on your region, your specific plan tier, or whether your account has been included in the current rollout. It is also possible the feature is toggled off in your settings or requires a specific setting to enable.
Common causes: You are on Claude Pro but Cowork is currently only in the Max tier for your region. Your app is up to date but the feature flag for your account has not been enabled yet. The Cowork section in settings is there but the toggle is off.
What to do: Confirm your plan level at https://claude.ai. Check the Cowork/Agent section of desktop settings carefully. If you believe you should have access but do not see the feature, contact support at https://support.claude.com with your account email and plan details.
Platform-Specific Notes
macOS: Cowork on macOS is built on Apple’s Virtualization framework and is generally the more stable of the two platforms right now. The most common issues here are permission-related (the OS enforces folder access strictly) and network-related (corporate environments, Little Snitch rules, DNS filtering).
Windows: Cowork runs natively on Windows with the same feature set as macOS. Most Windows-specific snags are environmental: VPN and corporate proxy conflicts, a local workspace socket that is sensitive to network configuration, and security software on managed machines. Check for app updates first. If you are on a managed work machine, your IT team’s security software is a frequent culprit. The community discussion at Anthropic GitHub is a useful place to find Windows-specific workarounds.
The Restart Sequence That Fixes Most Things
If you have identified your failure mode but are not ready to read the detailed guide, try this in order:
- Close the conversation and open a new one.
- Quit the Claude desktop app completely and relaunch it.
- Restart your machine.
- Reinstall the app if you have not updated recently.
Restarting clears stale state in the app, the workspace sandbox, and (on Windows) the network stack. It is not the most satisfying fix, but it is effective more often than it has any right to be.
Still Stuck?
If you have read this guide, identified the failure mode, read the detailed fix, and things still do not work, support is at https://support.claude.com. Include your plan type, your operating system and version, the exact error message, and what you were trying to do when it broke. The more specific you are, the faster the response.
Cowork is a research preview product, which means some bugs will take a while to get fixed. If your specific issue is a known bug, the support team can tell you that directly and give you a realistic timeline. That is a better outcome than spending another hour troubleshooting something that requires a patch on Anthropic’s end.
Frequently asked questions
Is Claude Cowork available on Windows?
Yes. Cowork is fully supported on Windows with the same features as the Mac version. Most Windows-specific issues trace back to network configuration (VPNs, proxies, corporate firewalls) or security software rather than the app itself. If something is not working, check for an app update first, then your network and security settings.
Do I need a paid plan to use Cowork?
Yes. Cowork requires a Claude Pro or Max subscription. It is not available on the free tier. If you just signed up for a paid plan, it may take a few minutes to activate.
Where is the toggle to enable Cowork?
Open Claude desktop, go to Settings, and look for the Cowork or Agent section. The toggle should be on. If you do not see this section, your plan may not include Cowork access.
How do I know if Anthropic is having an outage?
Check https://status.anthropic.com. If there is an active incident affecting the Claude API or desktop app, that is the cause and you need to wait for Anthropic to resolve it.
Cowork worked yesterday and stopped today. What changed?
The most common causes of sudden breakage are an app update that introduced a bug, an expired or lapsed subscription, a network or VPN configuration change, or an Anthropic service incident. Work through the universal first-aid checklist in this guide to find out which one.