[BUG] Cowork Workspace Start up Failure - Claude 1.1.9310 (cb30ac)

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?

The Cowork workspace fails to load due to the CDN serving a bad file - here's the analysis from Claude:

`Found the root cause. This is not a network issue on your end — it's a corrupted or truncated download artifact on Anthropic's CDN.
Here's what's happening: the app is trying to download Claude Code SDK v2.1.85 for the VM from downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst. Every single attempt gets the exact same result:

Expected size: 50,312,754 bytes
Actually transferred: 5,491,505 bytes (only ~11%)
File on disk: 16,682,192 bytes (starts with ELF header — it's the raw binary, not the compressed .zst)
Checksum: always 61ddcbf3... instead of the expected 3242468a...

The numbers are identical across all 11+ download attempts, even after you clicked "reinstall the workspace." That means the CDN is consistently serving a bad file. Switching networks wouldn't fix this because the problem is server-side.
Your VM was running fine on SDK v2.1.78. The app is now requiring v2.1.85, which is the broken download, and won't boot until it gets a clean copy.
What you can do right now:
There's not much to fix locally since this is a server-side artifact issue. You could try filing a bug via the thumbs-down button or through Anthropic support, referencing the specific URL and checksum mismatch. In the meantime, if you need Cowork urgently, you might check if there's a way to force it to keep using the v2.1.78 binary that was already working — though the app likely won't allow that.
TL;DR: Anthropic pushed Claude Code v2.1.85 and the linux-arm64 download artifact on their CDN appears to be corrupted or truncated. Nothing wrong on your end.

What Should Happen?

After a restart the Cowork session should startup the workspace.

Error Messages/Logs

[message]: 'Checksum verification failed'
2026-03-27 16:43:47 [info] [ClaudeCodeManager-VM] Downloading from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:43:47 [info] [download:8] Starting download from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:43:47 [info] [ClaudeCodeManager-VM] Downloaded file size: 16682192 bytes, transferred bytes: 5491505 bytes (expected: 50312754)
2026-03-27 16:43:47 [error] [ClaudeCodeManager-VM] Checksum mismatch: expected=3242468aae4e828486780e4d22b13f38fd3a1e165c6c8eba99396d92a3766063, actual=61ddcbf37eabfd7fcddf6dfacdf95849c7ef5160a7214ff9357d557e93e9f836
@826-03-27 16:43:48 [error] [ClaudeCodeManager-VM] File head: ELF���@�
2026-03-27 16:43:48 [error] [ClaudeCodeManager-VM] Download attempt 3/3 failed Error: Checksum verification failed
    at rHr.downloadBinaryForTarget (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:275:109251)
  [message]: 'Checksum verification failed'
2026-03-27 16:43:48 [error] [ClaudeCodeManager-VM] All download attempts failed
2026-03-27 16:43:48 [error] Session initialization failed for local_74569b80-1385-48d1-afb6-27bea9bcf367: Download failed. Check your internet connection and try again.
  unhealthy_reason: 'initialization_failed',
  error_message: 'Download failed. Check your internet connection and try again.',
2026-03-27 16:48:36 [error] [transport:sse] Stream read error: net::ERR_NETWORK_CHANGED
2026-03-27 16:48:37 [error] [transport:sse] Connection error: net::ERR_INTERNET_DISCONNECTED
2026-03-27 16:48:40 [error] [CustomPlugins] Failed to fetch remote plugins: net::ERR_NETWORK_CHANGED
2026-03-27 16:48:40 [error] [transport:sse] Connection error: net::ERR_NETWORK_CHANGED
2026-03-27 16:48:43 [info] [ClaudeCodeManager-VM] Downloading from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:48:43 [info] [download:9] Starting download from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:48:43 [info] [ClaudeCodeManager-VM] Downloaded file size: 16682192 bytes, transferred bytes: 5491505 bytes (expected: 50312754)
2026-03-27 16:48:43 [error] [ClaudeCodeManager-VM] Checksum mismatch: expected=3242468aae4e828486780e4d22b13f38fd3a1e165c6c8eba99396d92a3766063, actual=61ddcbf37eabfd7fcddf6dfacdf95849c7ef5160a7214ff9357d557e93e9f836
@826-03-27 16:48:45 [error] [ClaudeCodeManager-VM] File head: ELF���@�
2026-03-27 16:48:45 [error] [ClaudeCodeManager-VM] Download attempt 1/3 failed Error: Checksum verification failed
    at rHr.downloadBinaryForTarget (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:275:109251)
  [message]: 'Checksum verification failed'
2026-03-27 16:48:46 [info] [ClaudeCodeManager-VM] Downloading from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:48:46 [info] [download:10] Starting download from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:48:46 [info] [ClaudeCodeManager-VM] Downloaded file size: 16682192 bytes, transferred bytes: 5491505 bytes (expected: 50312754)
2026-03-27 16:48:46 [error] [ClaudeCodeManager-VM] Checksum mismatch: expected=3242468aae4e828486780e4d22b13f38fd3a1e165c6c8eba99396d92a3766063, actual=61ddcbf37eabfd7fcddf6dfacdf95849c7ef5160a7214ff9357d557e93e9f836
@826-03-27 16:48:47 [error] [ClaudeCodeManager-VM] File head: ELF���@�
2026-03-27 16:48:47 [error] [ClaudeCodeManager-VM] Download attempt 2/3 failed Error: Checksum verification failed
    at rHr.downloadBinaryForTarget (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:275:109251)
  [message]: 'Checksum verification failed'
2026-03-27 16:48:49 [info] [ClaudeCodeManager-VM] Downloading from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:48:49 [info] [download:11] Starting download from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:48:49 [info] [ClaudeCodeManager-VM] Downloaded file size: 16682192 bytes, transferred bytes: 5491505 bytes (expected: 50312754)
2026-03-27 16:48:49 [error] [ClaudeCodeManager-VM] Checksum mismatch: expected=3242468aae4e828486780e4d22b13f38fd3a1e165c6c8eba99396d92a3766063, actual=61ddcbf37eabfd7fcddf6dfacdf95849c7ef5160a7214ff9357d557e93e9f836
@826-03-27 16:48:50 [error] [ClaudeCodeManager-VM] File head: ELF���@�
2026-03-27 16:48:50 [error] [ClaudeCodeManager-VM] Download attempt 3/3 failed Error: Checksum verification failed
    at rHr.downloadBinaryForTarget (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:275:109251)
  [message]: 'Checksum verification failed'
2026-03-27 16:48:50 [error] [ClaudeCodeManager-VM] All download attempts failed
2026-03-27 16:48:55 [info] [reinstall] VM bundle deleted, restarting app
2026-03-27 16:49:01 [info] [ClaudeCodeManager-VM] Downloading from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:49:01 [info] [download:1] Starting download from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:49:02 [info] [SkillsPlugin] Delta: 0 to download, 0 to remove
2026-03-27 16:49:02 [info] [download:2] Starting download from https://claude.ai/api/organizations/4a2c46d0-139a-4ddc-9948-3a1d9a7d1feb/dxt/extensions/ant.dir.ant.anthropic.filesystem/download/0.2.1
2026-03-27 16:49:02 [info] [RemotePluginManager] Delta: 0 to download, 0 to remove
2026-03-27 16:49:02 [info] [RemotePluginManager] Delta: 0 to download, 0 to remove
2026-03-27 16:49:02 [info] [SkillsPlugin] Sync complete: 0 downloaded, 0 removed, 0 orphans cleaned
2026-03-27 16:49:03 [info] [ClaudeCodeManager-VM] Downloaded file size: 16682192 bytes, transferred bytes: 5491505 bytes (expected: 50312754)
2026-03-27 16:49:03 [error] [ClaudeCodeManager-VM] Checksum mismatch: expected=3242468aae4e828486780e4d22b13f38fd3a1e165c6c8eba99396d92a3766063, actual=61ddcbf37eabfd7fcddf6dfacdf95849c7ef5160a7214ff9357d557e93e9f836
@826-03-27 16:49:04 [error] [ClaudeCodeManager-VM] File head: ELF���@�
2026-03-27 16:49:04 [error] [ClaudeCodeManager-VM] Download attempt 1/3 failed Error: Checksum verification failed
    at rHr.downloadBinaryForTarget (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:275:109251)
  [message]: 'Checksum verification failed'
2026-03-27 16:49:04 [info] [RemotePluginManager] Sync complete: 0 downloaded, 0 removed, 0 orphans cleaned
2026-03-27 16:49:05 [info] [ClaudeCodeManager-VM] Downloading from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:49:05 [info] [download:3] Starting download from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:49:05 [info] [ClaudeCodeManager-VM] Downloaded file size: 16682192 bytes, transferred bytes: 5491505 bytes (expected: 50312754)
2026-03-27 16:49:05 [error] [ClaudeCodeManager-VM] Checksum mismatch: expected=3242468aae4e828486780e4d22b13f38fd3a1e165c6c8eba99396d92a3766063, actual=61ddcbf37eabfd7fcddf6dfacdf95849c7ef5160a7214ff9357d557e93e9f836
2026-03-27 16:49:05 [error] Failed to cache extension update ant.dir.ant.anthropic.filesystem@0.2.1: ENOENT: no such file or directory, open '/Users/ryanhutchinson/Library/Application Support/Claude/Extensions Update Cache/ant.dir.ant.anthropic.filesystem/dist/'
2026-03-27 16:49:05 [error] Failed to check/cache update for extension ant.dir.ant.anthropic.filesystem: [Error: ENOENT: no such file or directory, open '/Users/ryanhutchinson/Library/Application Support/Claude/Extensions Update Cache/ant.dir.ant.anthropic.filesystem/dist/'] {
2026-03-27 16:49:05 [info] [download:4] Starting download from https://claude.ai/api/organizations/4a2c46d0-139a-4ddc-9948-3a1d9a7d1feb/dxt/extensions/ant.dir.gh.anthropic.pdf-server-mcp/download/1.3.1
@826-03-27 16:49:06 [error] [ClaudeCodeManager-VM] File head: ELF���@�
2026-03-27 16:49:06 [error] [ClaudeCodeManager-VM] Download attempt 2/3 failed Error: Checksum verification failed
    at rHr.downloadBinaryForTarget (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:275:109251)
  [message]: 'Checksum verification failed'
2026-03-27 16:49:06 [info] [RemotePluginManager] Sync complete: 0 downloaded, 0 removed, 0 orphans cleaned
2026-03-27 16:49:08 [info] [ClaudeCodeManager-VM] Downloading from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:49:08 [info] [download:5] Starting download from https://downloads.claude.ai/claude-code-releases/2.1.85/linux-arm64/claude.zst
2026-03-27 16:49:08 [info] [ClaudeCodeManager-VM] Downloaded file size: 16682192 bytes, transferred bytes: 5491505 bytes (expected: 50312754)
2026-03-27 16:49:08 [error] [ClaudeCodeManager-VM] Checksum mismatch: expected=3242468aae4e828486780e4d22b13f38fd3a1e165c6c8eba99396d92a3766063, actual=61ddcbf37eabfd7fcddf6dfacdf95849c7ef5160a7214ff9357d557e93e9f836
2026-03-27 16:49:09 [error] Failed to cache extension update ant.dir.gh.anthropic.pdf-server-mcp@1.3.1: ENOENT: no such file or directory, open '/Users/ryanhutchinson/Library/Application Support/Claude/Extensions Update Cache/ant.dir.gh.anthropic.pdf-server-mcp/dist/'
2026-03-27 16:49:09 [error] Failed to check/cache update for extension ant.dir.gh.anthropic.pdf-server-mcp: [Error: ENOENT: no such file or directory, open '/Users/ryanhutchinson/Library/Application Support/Claude/Extensions Update Cache/ant.dir.gh.anthropic.pdf-server-mcp/dist/'] {
@826-03-27 16:49:09 [error] [ClaudeCodeManager-VM] File head: ELF���@�
2026-03-27 16:49:09 [error] [ClaudeCodeManager-VM] Download attempt 3/3 failed Error: Checksum verification failed
    at rHr.downloadBinaryForTarget (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index.js:275:109251)
  [message]: 'Checksum verification failed'
2026-03-27 16:49:09 [error] [ClaudeCodeManager-VM] All download attempts failed

Steps to Reproduce

Attempt to launch Cowork session

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.78

Claude Code Version

2.1.85

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_