Claude Desktop Dual Launcher

Claude Desktop Dual Launcher (Windows)

Sets up a second isolated Claude Desktop instance on Windows by leveraging Electron's --user-data-dir flag. Each instance has its own OAuth login, chat history, and local state — they can run at the same time, side by side.

Scope: Windows only (v1). The Windows Claude Desktop is a Microsoft Store MSIX package that internally still respects standard Electron command-line flags. macOS and Linux support is not implemented yet.

Arguments passed: $ARGUMENTS

When to use this skill

Trigger on any of:

• "double-open / dual-launch Claude Desktop"
• "run two Claude accounts at the same time"
• "switch Claude accounts without logging out every time"
• "I've hit the usage limit, can I use my other Pro account in parallel"
• "Claude Desktop multi-instance / second window"
• "--user-data-dir"
• "set up a [name] instance" where the user has previously set up dual-launcher

Dispatch on arguments

No args — explain + offer to set up

Briefly explain to the user what this skill does (two parallel Claude Desktop windows, each with its own account), confirm they're on Windows, then offer to run setup with a default instance name (secondary) or ask for a custom name.

Ask for the instance name the user wants (alphanumeric, hyphen, or underscore only). Suggest something memorable tied to the account's purpose ("work", "personal", an account nickname). Avoid offering the user's email or any identifying info — the name will appear on the desktop as Claude (<name>).lnk.

Then proceed to the "Run setup" step below with that name.

<instance-name> — run setup directly

Treat the first whitespace-separated token of $ARGUMENTS as the instance name. Validate it matches ^[A-Za-z0-9_-]+$. If not, ask the user to choose a simpler name.

Then proceed to "Run setup".

uninstall <instance-name> — remove an instance

Run scripts/uninstall.ps1 -InstanceName <name>. This deletes the desktop shortcut, the launcher script, and (after confirmation) the user-data-dir.

Run setup

Locate scripts/setup.ps1 relative to this SKILL.md and invoke it through PowerShell:

powershell -NoProfile -ExecutionPolicy Bypass -File "<path-to>/scripts/setup.ps1" -InstanceName "<name>"

The script will:

1. Scan C:\Program Files\WindowsApps\Claude_*\ for the latest Claude.exe
2. Create an isolated user-data-dir at %APPDATA%\Claude-<name>\
3. Deploy a self-healing launcher at %USERPROFILE%\.claude-dual-launcher\launch-<name>.ps1
4. Create a desktop shortcut Claude (<name>).lnk
5. Launch the new instance so the user can log in with the second account

Stream the script output to the user. When done, summarize what was created and remind the user that:

• Two instances can run at the same time. The original Claude Desktop launches from the taskbar/start menu like before; the new instance is opened via the desktop shortcut.
• Don't log in to the same account in both instances. Anthropic's sessions list will show two clients online for the same account, which may trigger security review.
• Each instance is independent. Logging out of one and signing in as a different account does not affect the other.
• If a Claude update breaks the desktop shortcut, the self-healing launcher script (%USERPROFILE%\.claude-dual-launcher\launch-<name>.ps1) auto-detects the new version's path. Either run it directly, or re-run this skill (setup) to refresh the shortcut.

Common follow-ups

• "How do I add a third instance?" — Re-invoke the skill with a different instance name (e.g. personal). Each name creates an independent instance.
• "How do I remove one?" — uninstall <name>.
• "Can I pin the new shortcut to taskbar?" — Yes, but Windows may visually merge it with the original Claude taskbar icon. Pinning is best after confirming the new shortcut works reliably.
• "What about Mac / Linux?" — Not supported yet in v1. The underlying --user-data-dir mechanism works on those platforms too, but the setup paths differ. PRs welcome.

How it actually works (background, for the curious)

Claude Desktop on Windows is shipped as a Microsoft Store MSIX package, but inside the package is a standard Electron application. Electron honors the --user-data-dir=<path> command-line flag, which redirects all of:

• OAuth tokens (stored in Local Storage\leveldb\)
• Chat history
• Window state
• Plugin enable/disable state

…to the specified directory instead of the default %APPDATA%\Claude\. This is the same dual-instance technique used by Discord, Slack, VS Code, and other Electron apps.

Note: Files under %USERPROFILE%\.claude\ (CLAUDE.md, MEMORY.md, plugin code, project settings) are not part of user-data-dir, so they are shared across all instances. This is usually what users want — global config and memory travel with the user, while sessions/auth are isolated.