Claude Desktop Not Working
Claude Desktop won’t open, crashes, shows MCP errors, or isn’t responding? Here’s how to check if Anthropic’s API is down and how to fix the most common Claude Desktop issues.
Check live Anthropic status
Prismix monitors Anthropic’s API every 5 minutes — faster than the official status page.
What’s not working?
Claude Desktop won’t open or crashes on launch
Most often caused by a corrupted or invalid claude_desktop_config.json. Delete or temporarily rename this file, then relaunch — Claude Desktop will recreate it with defaults.
Claude Desktop shows “MCP server disconnected”
The MCP server process failed to start or crashed. Check that required runtimes (Node.js, Python, etc.) are installed. Also validate your config file — a JSON syntax error stops all MCP servers from loading, even working ones.
Claude Desktop not responding or very slow
Claude Desktop relays all requests to Anthropic’s cloud API — it has no offline mode. If responses are slow or stop mid-message, check Anthropic API status first. Network issues and VPNs can also cause intermittent timeouts.
Claude Desktop can’t access files or tools
File access requires an MCP server with filesystem permissions. On macOS, Claude Desktop also needs Full Disk Access in System Settings → Privacy & Security. Without this, file reads fail silently.
5 fixes to try in order
Check if Anthropic’s API is down
Visit prismix.dev/service/anthropic. If there’s an active incident, Claude Desktop will fail to respond until Anthropic resolves it. No local fix will help during an API outage.
Validate your config file
Open ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows) and paste it into jsonlint.com. A single missing comma or bracket will prevent Claude Desktop from loading MCP servers.
Restart Claude Desktop
macOS: Cmd+Q to quit, then reopen from Applications. Check Activity Monitor for stuck Claude processes and force-quit them first. Windows: Right-click the tray icon → Quit, then reopen. Config file changes require a full restart.
Verify MCP server dependencies
For each MCP server in your config, confirm its runtime is installed and accessible from terminal (not just your IDE). Run node --version or python3 --version in a new terminal window. If PATH issues exist in terminal, Claude Desktop will see the same problem.
Update or reinstall
Claude Desktop auto-updates, but if stuck on an old version: download the latest from claude.ai/download. On macOS, drag to Applications to overwrite. On Windows, run the installer over the existing install. Your conversation history is stored locally and is preserved.
MCP config file location
macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json
After any edit to this file, Claude Desktop must be fully restarted to pick up changes.
Monitor Anthropic API uptime in real time
Prismix tracks Anthropic every 5 minutes — free, no account needed.
FAQ
Does Claude Desktop work offline?
No. Claude Desktop requires an active internet connection for every message — it sends all requests to Anthropic’s cloud API. There is no local model or offline mode. MCP servers can run locally, but the Claude model itself is always remote.
Why does Claude Desktop use more memory over time?
Long conversations accumulate context in memory. Starting a new chat resets the context window. If Claude Desktop is consistently slow, try starting fresh conversations rather than continuing very long threads.
Can I use Claude Desktop without configuring MCP servers?
Yes. MCP servers are optional — Claude Desktop works for standard chat without any MCP configuration. If you haven’t set up any MCP servers, you can safely delete the config file and Claude Desktop will work with defaults.
Where are Claude Desktop conversation logs stored?
Conversation history is stored locally on your machine under the Claude application data directory. Reinstalling Claude Desktop does not delete your history. The MCP server logs appear in the Claude Desktop developer console (accessible via the app menu).