# Claude Cowork not working on Windows: fixes from Anthropic's docs

> Missing HCS services, error 0x80073D28 and 0x80073CF6, and Fast Startup issues, with the steps Anthropic lists for each.

URL: https://claudegpt.si/news/claude-cowork-not-working-windows  
Published: 2026-11-03T14:51:53.145Z  
Author: ClaudeGPT Si Newsroom  
Section: Guides  
Topics: Claude, Claude Cowork, Claude desktop, Windows, Troubleshooting  
Publisher: ClaudeGPT Si

## Key takeaways

- Cowork on Windows needs the Virtual Machine Platform feature and an install done with administrator privileges.
- Anthropic says to use Restart instead of shut down, because Fast Startup can leave virtualization services uninitialized.
- Errors 0x80073D28 and 0x80073CF6 are fixed by running the current Claude installer as administrator.

If Claude Cowork is not working on Windows, the cause is usually one of three things: Claude was installed without administrator rights, the Windows Virtual Machine Platform feature is off or half set up, or the virtualization services did not start after a shutdown. Each has a fix in [Anthropic's guide to deploying Claude Desktop for Windows](https://support.claude.com/en/articles/12622703-deploy-claude-desktop-for-windows), and this page walks through them in order. Information is from that article as of November 3, 2026.

Cowork runs its work in an isolated virtual machine on your computer, according to Anthropic's [install guide](https://support.claude.com/en/articles/10065433-install-claude-desktop). That is why most Windows problems come down to virtualization and installation permissions, not your account or your internet connection.

## What Cowork needs on Windows

Anthropic lists these requirements for Windows:

- The **Virtual Machine Platform** Windows feature, turned on and followed by a restart.
- An install done with administrator privileges. Without admin rights Claude installs, but Cowork is not available.
- A machine that can run virtual machines. Virtual machines and VDI environments without nested virtualization can't run Cowork.

If you are not sure which check is failing, open Claude Desktop and go to **Help > Troubleshooting > Show Logs**. Open `supported-features-info.json`. It shows which check failed, so you can skip to the matching fix below.

## How to fix "missing HCS services"

This error means the Virtual Machine Platform stack is not registered, even though Claude itself installed. The services involved are HNS, vmcompute and vfpext.

1. Open PowerShell as administrator.
2. Check the feature and the services:

```
Get-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform
Get-Service vmcompute, hns
```

3. If the feature is off, or the services are missing, enable it:

```
Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform -All
```

4. Restart the computer. The feature takes effect only after a restart.

## How to fix Cowork after a shutdown

Use **Restart**, not shut down and power on. Anthropic says that with Windows Fast Startup enabled, a shutdown can leave the virtualization services uninitialized. If Cowork worked yesterday and fails today, restart once before trying anything else.

## How to fix error 0x80073D28 or "administrator access is required"

Windows registers Cowork's background service only when Claude is installed with administrator privileges. A per-user install without admin rights hits error 0x80073D28, because Windows won't register the package without the Cowork service.

Run Claude Setup again with administrator approval. IT teams can instead provision the package for every user on the machine:

```
Add-AppxProvisionedPackage -Online -PackagePath "Claude.msix" -SkipLicense -Regions "all"
```

## How to fix error 0x80073CF6

This error means an earlier install left the package partly registered. Anthropic's steps:

1. Restart the device.
2. Run the current installer as administrator, which is the newer installation the error asks for.
3. If the error stays, contact Anthropic support and attach `ClaudeSetup.log` from your Temp folder.

The installer's repair removes local app data, including settings, your saved sign-in and files saved only in Cowork. Chat history and files in your own folders are not affected.

## How to fix Cowork when VMware or VirtualBox is installed

Other hypervisors can change how Windows starts its own. In an elevated prompt, run `bcdedit` and look at `hypervisorlaunchtype`. If it is not `Auto`, set it and restart:

```
bcdedit /set hypervisorlaunchtype auto
```

## When none of this works

The Anthropic article doesn't cover every error. It does not describe Windows S mode or error 0x80070569, so this page makes no claims about them. If the logs point to a check this page doesn't cover, contact Anthropic support through the "How to get support" link in the [install guide](https://support.claude.com/en/articles/10065433-install-claude-desktop), and include the Windows version, the Claude Desktop version and the exact error text.

For how Cowork differs from Claude Code once it is running, see our [comparison of Claude Code and Cowork](https://claudegpt.si/news/claude-code-vs-cowork).

## Quick checklist before you contact support

Work through these in order. Confirm Claude was installed with administrator approval. Confirm Virtual Machine Platform shows as enabled and that `vmcompute` and `hns` are listed by `Get-Service`. Restart the machine instead of shutting it down. Check `hypervisorlaunchtype` if another hypervisor is installed. Then read `supported-features-info.json` in the logs to see which check still fails.

## Frequently asked questions

### Why is Cowork missing in Claude Desktop on Windows?

Anthropic says Claude installed without administrator privileges installs without Cowork. Run Claude Setup again with administrator approval, then check Help > Troubleshooting > Show Logs for the failing check.

### How do I enable Virtual Machine Platform for Claude Cowork?

In an administrator PowerShell, run Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform -All, then restart. The feature takes effect only after a restart.

### Does Cowork work in a virtual machine on Windows?

Not without nested virtualization. Anthropic says virtual machines and VDI environments without nested virtualization can't run Cowork.

### Will reinstalling Claude delete my chats?

For error 0x80073CF6, Anthropic says the installer's repair removes settings, saved sign-in and files saved only in Cowork. Chat history and files in your own folders are not affected.

## Sources

- [Deploy Claude Desktop for Windows](https://support.claude.com/en/articles/12622703-deploy-claude-desktop-for-windows), Anthropic
- [Install Claude Desktop](https://support.claude.com/en/articles/10065433-install-claude-desktop), Anthropic